configure: Refactor platform defaults

The main idea was to move complexity from source (and Makefiles)
into configure.ac, because otherwise these must replicate the
"same" branching, often resulting in diversions. Better to keep
the logic in one place (configure.ac) and set additional variables
to be used directly by source code and Makefiles.

Notably this introduce the "using_*" platform flags, which should
be considered constants. There is USING_X11, which actually tells,
if the build uses the platform's X11 (and I opted for the removal
of HAVE_FEATURE_X11). I also consider variables constant, after
they have been exported by AC_SUBST, which should never be
conditional, or some AC_DEFINE set them for a config header.

A large block of defaults depends on $using_x11, so we set them to
the same value, but just if the platform doesn't set it.

The other important flag is $using_freetype_fontconfig, if the
platform uses freetype and fontconfig. The headless plugin uses
cairo for its drawing operations and freetype+fontconfig for text,
so $test_cairo = $using_freetype_fontconfig. This is independent
from a the cairo canvas!

The OpenGL X11 code now depends on USING_X11, but it doesn't yet
reflect the filter in Library_vcl.mk protecting glx. I don't know
how correct this glx filter is, seeing that the source code just
checked for "UNX - some  non-X11 targets".

Change-Id: Id1ba1a967a5d8d10ee217458be879ed00459f7e6
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/116440
Tested-by: Jenkins
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>

15 files changed, 191 insertions, 221 deletions

diff --git a/config_host.mk.in b/config_host.mk.in
index b6288472ea6d..f2117f306615 100644
--- a/config_host.mk.in
+++ b/config_host.mk.in
@@ -163,6 +163,7 @@ export ENABLE_GSTREAMER_1_0=@ENABLE_GSTREAMER_1_0@
 export ENABLE_GTK3=@ENABLE_GTK3@
 export ENABLE_GTK4=@ENABLE_GTK4@
 export DISABLE_GUI=@DISABLE_GUI@
+export ENABLE_HEADLESS=@ENABLE_HEADLESS@
 export ENABLE_HTMLHELP=@ENABLE_HTMLHELP@
 export ENABLE_JAVA=@ENABLE_JAVA@
 export ENABLE_LDAP=@ENABLE_LDAP@
diff --git a/config_host/config_features.h.in b/config_host/config_features.h.in
index c557a405ceb1..ef09850492a9 100644
--- a/config_host/config_features.h.in
+++ b/config_host/config_features.h.in
@@ -7,13 +7,6 @@
 #ifndef CONFIG_FEATURES_H
 #define CONFIG_FEATURES_H
 
-/* X11
- *
- * Whether we are building code to run in an X11 environment.
- */
-
-#define HAVE_FEATURE_X11 0
-
 /* AVMEDIA - Whether to have functionality to display and manipulate
  * embedded AV media in documents
  */
@@ -119,7 +112,7 @@
 /*
  * Whether User Interface is available
  */
-#define HAVE_FEATURE_UI 1
+#define HAVE_FEATURE_UI 0
 
 /*
  * Whether PDF import is available
diff --git a/config_host/config_vclplug.h.in b/config_host/config_vclplug.h.in
index 1a44907fb087..db0c7a8be201 100644
--- a/config_host/config_vclplug.h.in
+++ b/config_host/config_vclplug.h.in
@@ -12,11 +12,18 @@ Settings about which desktops have support enabled.
  */
 #define USING_X11 0
 
+/**
+ * Set the enabled platform plugins
+ */
 #define ENABLE_GTK3 0
 #define ENABLE_GTK3_KDE5 0
+#define ENABLE_HEADLESS 0
 #define ENABLE_KF5 0
 #define ENABLE_QT5 0
 
+/**
+ * Additional settings for the plugins
+ */
 #define ENABLE_GSTREAMER_1_0 0
 #define QT5_HAVE_GOBJECT 0
 #define QT5_USING_X11 0
diff --git a/configure.ac b/configure.ac
index 736c772eebee..9fcac74e93ef 100644
--- a/configure.ac
+++ b/configure.ac
@@ -800,26 +800,27 @@ if test "$enable_android_editing" = yes; then
 fi
 AC_SUBST([ENABLE_ANDROID_EDITING])
 
-dnl ===================================================================
-dnl The following is a list of supported systems.
-dnl Sequential to keep the logic very simple
-dnl These values may be checked and reset later.
-dnl ===================================================================
-#defaults unless the os test overrides this:
+# ===================================================================
+#
+# Start initial platform setup
+#
+# The using_* variables reflect platform support and should not be
+# changed after the "End initial platform setup" block.
+# This is also true for most test_* variables.
+# ===================================================================
 build_crypto=yes
 test_cmis=yes
 test_curl=yes
-test_randr=yes
-test_xrender=yes
-test_cups=yes
-test_dbus=yes
-test_fontconfig=yes
-test_cairo=no
 test_gdb_index=no
 test_split_debug=no
-test_openldap=yes
 test_webdav=yes
 
+# There is currently just iOS not using salplug, so this explicitly enables it.
+# must: using_freetype_fontconfig
+#  may: using_headless_plugin defaults to $using_freetype_fontconfig
+using_vclplug=yes
+# must: using_x11
+
 # Default values, as such probably valid just for Linux, set
 # differently below just for Mac OSX, but at least better than
 # hardcoding these as we used to do. Much of this is duplicated also
@@ -843,8 +844,8 @@ host_cpu_for_clang="$host_cpu"
 case "$host_os" in
 
 solaris*)
-    build_gstreamer_1_0=yes
-    test_freetype=yes
+    using_freetype_fontconfig=yes
+    using_x11=yes
     build_skia=yes
     _os=SunOS
 
@@ -869,31 +870,24 @@ solaris*)
     ;;
 
 linux-gnu*|k*bsd*-gnu*)
-    build_gstreamer_1_0=yes
-    test_kf5=yes
-    test_gtk3_kde5=yes
+    using_freetype_fontconfig=yes
+    using_x11=yes
     build_skia=yes
     test_gdb_index=yes
     test_split_debug=yes
-    if test "$enable_fuzzers" != yes; then
-        test_freetype=yes
-        test_fontconfig=yes
-    else
-        test_freetype=no
-        test_fontconfig=no
-        BUILD_TYPE="$BUILD_TYPE FONTCONFIG FREETYPE"
+    if test "$enable_fuzzers" = yes; then
+        test_system_freetype=no
     fi
     _os=Linux
     ;;
 
 gnu)
-    test_randr=no
-    test_xrender=no
+    using_freetype_fontconfig=yes
+    using_x11=no
     _os=GNU
      ;;
 
 cygwin*|wsl*)
-
     # When building on Windows normally with MSVC under Cygwin,
     # configure thinks that the host platform (the platform the
     # built code will run on) is Cygwin, even if it obviously is
@@ -905,13 +899,8 @@ cygwin*|wsl*)
     # look at $host etc that much, it mostly uses its own $_os
     # variable, set here in this case statement.
 
-    test_cups=no
-    test_dbus=no
-    test_randr=no
-    test_xrender=no
-    test_freetype=no
-    test_fontconfig=no
-    test_openldap=no
+    using_freetype_fontconfig=no
+    using_x11=no
     build_skia=yes
     _os=WINNT
 
@@ -926,11 +915,8 @@ cygwin*|wsl*)
     ;;
 
 darwin*|macos*) # macOS
-    test_randr=no
-    test_xrender=no
-    test_freetype=no
-    test_fontconfig=no
-    test_dbus=no
+    using_freetype_fontconfig=no
+    using_x11=no
     if test -n "$LODE_HOME" ; then
         mac_sanitize_path
         AC_MSG_NOTICE([sanitized the PATH to $PATH])
@@ -965,14 +951,11 @@ darwin*|macos*) # macOS
 ;;
 
 ios*) # iOS
+    using_freetype_fontconfig=no
+    using_vclplug=no
+    using_x11=no
     build_crypto=no
     test_cmis=no
-    test_randr=no
-    test_xrender=no
-    test_freetype=no
-    test_fontconfig=no
-    test_dbus=no
-    test_openldap=no
     test_webdav=no
     if test -n "$LODE_HOME" ; then
         mac_sanitize_path
@@ -980,7 +963,6 @@ ios*) # iOS
     fi
     enable_gpgmepp=no
     _os=iOS
-    test_cups=no
     enable_mpl_subset=yes
     enable_lotuswordpro=no
     enable_coinmp=no
@@ -1013,10 +995,8 @@ ios*) # iOS
 ;;
 
 freebsd*)
-    build_gstreamer_1_0=yes
-    test_kf5=yes
-    test_gtk3_kde5=yes
-    test_freetype=yes
+    using_freetype_fontconfig=yes
+    using_x11=yes
     build_skia=yes
     AC_MSG_CHECKING([the FreeBSD operating system release])
     if test -n "$with_os_version"; then
@@ -1041,44 +1021,49 @@ freebsd*)
     ;;
 
 *netbsd*)
-    build_gstreamer_1_0=yes
-    test_kf5=yes
-    test_gtk3_kde5=yes
-    test_freetype=yes
+    using_freetype_fontconfig=yes
+    using_x11=yes
+    test_gtk3_kde5=no
     build_skia=yes
     PTHREAD_LIBS="-pthread -lpthread"
     _os=NetBSD
     ;;
 
 aix*)
+    using_freetype_fontconfig=yes
+    using_x11=yes
     test_randr=no
-    test_freetype=yes
+    test_gstreamer_1_0=no
     PTHREAD_LIBS=-pthread
     _os=AIX
     ;;
 
 openbsd*)
-    test_freetype=yes
+    using_freetype_fontconfig=yes
+    using_x11=yes
     PTHREAD_CFLAGS="-D_THREAD_SAFE"
     PTHREAD_LIBS="-pthread"
     _os=OpenBSD
     ;;
 
 dragonfly*)
-    build_gstreamer_1_0=yes
-    test_kf5=yes
-    test_gtk3_kde5=yes
-    test_freetype=yes
+    using_freetype_fontconfig=yes
+    using_x11=yes
     build_skia=yes
     PTHREAD_LIBS="-pthread"
     _os=DragonFly
     ;;
 
 linux-android*)
+    using_freetype_fontconfig=yes
+    using_headless_plugin=no
+    using_x11=no
     build_crypto=no
-    build_gstreamer_1_0=no
+    test_system_freetype=no
+    test_webdav=no
     enable_lotuswordpro=no
     enable_mpl_subset=yes
+    enable_cairo_canvas=no
     enable_coinmp=yes
     enable_lpsolve=no
     enable_mariadb_sdbc=no
@@ -1086,31 +1071,18 @@ linux-android*)
     enable_odk=no
     enable_postgresql_sdbc=no
     enable_python=no
-    test_cups=no
-    test_dbus=no
-    test_fontconfig=no
-    test_freetype=no
-    test_kf5=no
-    test_qt5=no
-    test_gtk3_kde5=no
-    test_openldap=no
-    test_randr=no
-    test_webdav=no
-    test_xrender=no
     _os=Android
 
     AC_DEFINE(HAVE_FT_FACE_GETCHARVARIANTINDEX)
-    BUILD_TYPE="$BUILD_TYPE CAIRO FONTCONFIG FREETYPE"
     ;;
 
 haiku*)
-    test_cups=no
-    test_dbus=no
-    test_randr=no
-    test_xrender=no
-    test_freetype=yes
+    using_freetype_fontconfig=yes
+    using_x11=no
+    test_gtk3_kde5=no
+    test_kf5=yes
+    test_openldap=yes
     enable_odk=no
-    enable_gstreamer_1_0=no
     enable_coinmp=no
     enable_pdfium=no
     enable_sdremote=no
@@ -1120,27 +1092,19 @@ haiku*)
     ;;
 
 emscripten)
-    build_gstreamer_1_0=no
-    enable_lpsolve=no
-    enable_report_builder=no
-    with_theme="breeze"
+    using_freetype_fontconfig=yes
+    using_x11=no
+    enable_compiler_plugins=no
     test_cmis=no
-    test_cups=no
-    test_curl=no
-    test_dbus=no
-    test_fontconfig=no
-    test_freetype=no
-    test_gtk=no
-    test_randr=no
     test_webdav=no
-    test_xrender=no
-    enable_postgresql_sdbc=no
     enable_firebird_sdbc=no
+    enable_lpsolve=no
     enable_mariadb_sdbc=no
+    enable_postgresql_sdbc=no
+    enable_report_builder=no
     with_system_zlib=no
+    with_theme="breeze"
     _os=Emscripten
-
-    BUILD_TYPE="$BUILD_TYPE FONTCONFIG FREETYPE"
     ;;
 
 *)
@@ -1150,6 +1114,73 @@ esac
 
 AC_SUBST(HOST_PLATFORM)
 
+if test -z "$using_x11" -o -z "$using_freetype_fontconfig"; then
+    AC_MSG_ERROR([You must set \$using_freetype_fontconfig and \$using_x11 for your platform])
+fi
+
+# Set defaults, if not set by platform
+test "${test_cups+set}" = set || test_cups="$using_x11"
+test "${test_dbus+set}" = set || test_dbus="$using_x11"
+test "${test_gstreamer_1_0+set}" = set || test_gstreamer_1_0="$using_x11"
+test "${test_gtk3+set}" = set || test_gtk3="$using_x11"
+test "${test_gtk4+set}" = set || test_gtk4="$using_x11"
+test "${test_kf5+set}" = set || test_kf5="$using_x11"
+test "${test_openldap+set}" = set || test_openldap="$using_x11"
+# don't handle test_qt5, so it can disable test_kf5 later
+test "${test_randr+set}" = set || test_randr="$using_x11"
+test "${test_xrender+set}" = set || test_xrender="$using_x11"
+test "${using_headless_plugin+set}" = set || using_headless_plugin="$using_freetype_fontconfig"
+
+test "${test_gtk3_kde5+set}" != set -a "$test_kf5" = yes -a "$test_gtk3" = yes && test_gtk3_kde5="yes"
+test "${test_system_fontconfig+set}" != set -a "${test_system_freetype+set}" = set && test_system_fontconfig="$test_system_freetype"
+test "${test_system_freetype+set}" != set -a "${test_system_fontconfig+set}" = set && test_system_freetype="$test_system_fontconfig"
+
+# convenience / platform overriding "fixes"
+# Don't sort!
+test "$test_kf5" = yes -a "$test_qt5" = no && test_kf5=no
+test "$test_kf5" = yes && test_qt5=yes
+test "$test_gtk3" != yes -o "$test_kf5" != yes && test_gtk3_kde5=no
+test "$using_freetype_fontconfig" = no && using_headless_plugin=no
+test "$using_freetype_fontconfig" = yes && test_cairo=yes
+
+# Keep in sync with the above $using_x11 depending test default list
+disable_x11_tests()
+{
+    test_cups=no
+    test_dbus=no
+    test_gstreamer_1_0=no
+    test_gtk3_kde5=no
+    test_gtk3=no
+    test_gtk4=no
+    test_kf5=no
+    test_openldap=no
+    test_qt5=no
+    test_randr=no
+    test_xrender=no
+}
+
+test "$using_x11" = yes && USING_X11=TRUE
+
+if test "$using_freetype_fontconfig" = yes; then
+    if test "$using_headless_plugin" = yes; then
+        AC_DEFINE(ENABLE_HEADLESS)
+        ENABLE_HEADLESS=TRUE
+    fi
+fi
+
+AC_SUBST(ENABLE_HEADLESS)
+
+AC_MSG_NOTICE([VCL platform uses freetype+fontconfig: $using_freetype_fontconfig])
+AC_MSG_NOTICE([VCL platform uses headless plugin: $using_headless_plugin])
+AC_MSG_NOTICE([VCL platform uses vclplug: $using_vclplug])
+AC_MSG_NOTICE([VCL platform uses X11: $using_x11])
+
+# ===================================================================
+#
+# End initial platform setup
+#
+# ===================================================================
+
 if test "$_os" = "Android" ; then
     # Verify that the NDK and SDK options are proper
     if test -z "$with_android_ndk"; then
@@ -3674,7 +3705,6 @@ reg_get_value_64()
 case "$host_os" in
 cygwin*|wsl*)
     COM=MSC
-    USING_X11=
     OS=WNT
     RTL_OS=Windows
     if test "$GNUMAKE_WIN_NATIVE" = "TRUE" ; then
@@ -4715,14 +4745,12 @@ AC_SUBST(ENABLE_OPTIMIZED_DEBUG)
 
 #
 # determine CPUNAME, OS, ...
-# The USING_X11 flag tells whether the host os uses X by default. Can be overridden with the --without-x option.
 #
 case "$host_os" in
 
 aix*)
     COM=GCC
     CPUNAME=POWERPC
-    USING_X11=TRUE
     OS=AIX
     RTL_OS=AIX
     RTL_ARCH=PowerPC
@@ -4736,7 +4764,6 @@ cygwin*|wsl*)
 
 darwin*|macos*)
     COM=GCC
-    USING_X11=
     OS=MACOSX
     RTL_OS=MacOSX
     P_SEP=:
@@ -4767,7 +4794,6 @@ darwin*|macos*)
 
 ios*)
     COM=GCC
-    USING_X11=
     OS=iOS
     RTL_OS=iOS
     P_SEP=:
@@ -4789,7 +4815,6 @@ ios*)
 
 dragonfly*)
     COM=GCC
-    USING_X11=TRUE
     OS=DRAGONFLY
     RTL_OS=DragonFly
     P_SEP=:
@@ -4813,7 +4838,6 @@ dragonfly*)
 
 freebsd*)
     COM=GCC
-    USING_X11=TRUE
     RTL_OS=FreeBSD
     OS=FREEBSD
     P_SEP=:
@@ -4852,7 +4876,6 @@ freebsd*)
 
 haiku*)
     COM=GCC
-    USING_X11=
     GUIBASE=haiku
     RTL_OS=Haiku
     OS=HAIKU
@@ -4877,7 +4900,6 @@ haiku*)
 
 kfreebsd*)
     COM=GCC
-    USING_X11=TRUE
     OS=LINUX
     RTL_OS=kFreeBSD
     P_SEP=:
@@ -4902,7 +4924,6 @@ kfreebsd*)
 
 linux-gnu*)
     COM=GCC
-    USING_X11=TRUE
     OS=LINUX
     RTL_OS=Linux
     P_SEP=:
@@ -5025,7 +5046,6 @@ linux-gnu*)
 
 linux-android*)
     COM=GCC
-    USING_X11=
     OS=ANDROID
     RTL_OS=Android
     P_SEP=:
@@ -5060,7 +5080,6 @@ linux-android*)
 
 *netbsd*)
     COM=GCC
-    USING_X11=TRUE
     OS=NETBSD
     RTL_OS=NetBSD
     P_SEP=:
@@ -5094,7 +5113,6 @@ linux-android*)
 
 openbsd*)
     COM=GCC
-    USING_X11=TRUE
     OS=OPENBSD
     RTL_OS=OpenBSD
     P_SEP=:
@@ -5119,7 +5137,6 @@ openbsd*)
 
 solaris*)
     COM=GCC
-    USING_X11=TRUE
     OS=SOLARIS
     RTL_OS=Solaris
     P_SEP=:
@@ -5149,7 +5166,6 @@ solaris*)
 
 emscripten*)
     COM=GCC
-    USING_X11=
     OS=EMSCRIPTEN
     RTL_OS=Emscripten
     P_SEP=:
@@ -5177,18 +5193,26 @@ fi
 
 DISABLE_GUI=""
 if test "$enable_gui" = "no"; then
-    if test "$USING_X11" != TRUE; then
+    if test "$using_x11" != yes; then
         AC_MSG_ERROR([$host_os operating system is not suitable to build LibreOffice with --disable-gui.])
     fi
     USING_X11=
     DISABLE_GUI=TRUE
-    AC_DEFINE(HAVE_FEATURE_UI,0)
-    test_cairo=yes
+else
+    AC_DEFINE(HAVE_FEATURE_UI)
 fi
 AC_SUBST(DISABLE_GUI)
 
-if test "$USING_X11" = TRUE; then
-    AC_DEFINE(USING_X11)
+if test "$using_x11" = yes; then
+    if test "$USING_X11" = TRUE; then
+        AC_DEFINE(USING_X11)
+    else
+        disable_x11_tests
+    fi
+else
+    if test "$USING_X11" = TRUE; then
+        AC_MSG_ERROR([Platform doesn't support X11 (\$using_x11), but \$USING_X11 is set!])
+    fi
 fi
 
 WORKDIR="${BUILDDIR}/workdir"
@@ -5353,11 +5377,13 @@ if test "$cross_compiling" = "yes"; then
     # Don't bother having configure look for stuff not needed for the build platform anyway
     ./configure \
         --build="$build_alias" \
+        --disable-cairo-canvas \
         --disable-cups \
         --disable-firebird-sdbc \
         --disable-gpgmepp \
         --disable-gstreamer-1-0 \
         --disable-gtk3 \
+        --disable-gtk4 \
         --disable-mariadb-sdbc \
         --disable-nss \
         --disable-online-update \
@@ -5600,28 +5626,6 @@ if test $_os != "WINNT" -a $_os != "Darwin"; then
 fi
 AC_SUBST(ENABLE_OOENV)
 
-if test "$USING_X11" != TRUE; then
-    # be sure to do not mess with unneeded stuff
-    test_randr=no
-    test_xrender=no
-    test_cups=no
-    test_dbus=no
-    build_gstreamer_1_0=no
-    test_kf5=no
-    test_qt5=no
-    test_gtk3_kde5=no
-    enable_cairo_canvas=no
-fi
-
-if test "$OS" = "HAIKU"; then
-    enable_cairo_canvas=yes
-    test_kf5=yes
-fi
-
-if test "$test_kf5" = "yes"; then
-    test_qt5=yes
-fi
-
 if test "$test_kf5" = "yes" -a "$enable_kf5" = "yes"; then
     if test "$enable_qt5" = "no"; then
         AC_MSG_ERROR([KF5 support depends on QT5, so it conflicts with --disable-qt5])
@@ -5652,11 +5656,18 @@ fi
 AC_SUBST(ENABLE_CUPS)
 
 # fontconfig checks
-if test "$test_fontconfig" = "yes"; then
+if test "$using_freetype_fontconfig" = yes; then
+    AC_MSG_CHECKING([which fontconfig to use])
+fi
+if test "$using_freetype_fontconfig" = yes -a "$test_system_fontconfig" != no; then
+    AC_MSG_RESULT([external])
     PKG_CHECK_MODULES([FONTCONFIG], [fontconfig >= 2.4.1])
     SYSTEM_FONTCONFIG=TRUE
     FilterLibs "${FONTCONFIG_LIBS}"
     FONTCONFIG_LIBS="${filteredlibs}"
+elif test "$using_freetype_fontconfig" = yes; then
+    AC_MSG_RESULT([internal])
+    BUILD_TYPE="$BUILD_TYPE FONTCONFIG"
 fi
 AC_SUBST(FONTCONFIG_CFLAGS)
 AC_SUBST(FONTCONFIG_LIBS)
@@ -9301,8 +9312,11 @@ fi
 dnl ===================================================================
 dnl Check whether freetype is available
 dnl ===================================================================
-if test  "$test_freetype" = "yes"; then
-    AC_MSG_CHECKING([whether freetype is available])
+if test "$using_freetype_fontconfig" = yes; then
+    AC_MSG_CHECKING([which freetype to use])
+fi
+if test "$using_freetype_fontconfig" = yes -a "$test_system_freetype" != no; then
+    AC_MSG_RESULT([external])
     # FreeType has 3 different kinds of versions
     # * release, like 2.4.10
     # * libtool, like 13.0.7 (this what pkg-config returns)
@@ -9315,13 +9329,15 @@ if test  "$test_freetype" = "yes"; then
     FilterLibs "${FREETYPE_LIBS}"
     FREETYPE_LIBS="${filteredlibs}"
     SYSTEM_FREETYPE=TRUE
-else
+elif test "$using_freetype_fontconfig" = yes; then
+    AC_MSG_RESULT([internal])
     FREETYPE_CFLAGS="${ISYSTEM}${WORKDIR}/UnpackedTarball/freetype/include"
     if test "x$ac_config_site_64bit_host" = xYES; then
         FREETYPE_LIBS="-L${WORKDIR}/UnpackedTarball/freetype/instdir/lib64 -lfreetype"
     else
         FREETYPE_LIBS="-L${WORKDIR}/UnpackedTarball/freetype/instdir/lib -lfreetype"
     fi
+    BUILD_TYPE="$BUILD_TYPE FREETYPE"
 fi
 AC_SUBST(FREETYPE_CFLAGS)
 AC_SUBST(FREETYPE_LIBS)
@@ -10648,15 +10664,6 @@ else
     fi
 fi
 
-AC_MSG_CHECKING([whether to use X11])
-dnl ***************************************
-dnl testing for X libraries and includes...
-dnl ***************************************
-if test "$USING_X11" = TRUE; then
-    AC_DEFINE(HAVE_FEATURE_X11)
-fi
-AC_MSG_RESULT([$USING_X11])
-
 if test "$USING_X11" = TRUE; then
     AC_PATH_X
     AC_PATH_XTRA
@@ -11502,7 +11509,9 @@ if test "$_os" = "WINNT"; then
 elif test "$_os" = "Darwin"; then
     R="$R osx"
 elif test "$_os" = "iOS"; then
-    R="ios (builtin)"
+    R="ios"
+elif test "$_os" = Android; then
+    R="android"
 fi
 
 build_vcl_plugins="$R"
@@ -11519,11 +11528,10 @@ dnl ===================================================================
 
 GTK3_CFLAGS=""
 GTK3_LIBS=""
-if test "x$enable_gtk3" = "xyes" -o "x$enable_gtk3_kde5" = "xyes"; then
+if test "$test_gtk3" = yes -a "x$enable_gtk3" = "xyes" -o "x$enable_gtk3_kde5" = "xyes"; then
     if test "$with_system_cairo" = no; then
         add_warning 'Non-system cairo combined with gtk3 is assumed to cause trouble; proceed at your own risk.'
     fi
-    : ${with_system_cairo:=yes}
     PKG_CHECK_MODULES(GTK3, gtk+-3.0 >= 3.20 gtk+-unix-print-3.0 gmodule-no-export-2.0 glib-2.0 >= 2.38 cairo)
     GTK3_CFLAGS=$(printf '%s' "$GTK3_CFLAGS" | sed -e "s/-I/${ISYSTEM?}/g")
     GTK3_CFLAGS="$GTK3_CFLAGS -DGDK_DISABLE_DEPRECATED -DGTK_DISABLE_DEPRECATED"
@@ -11542,11 +11550,10 @@ AC_SUBST(GTK3_CFLAGS)
 
 GTK4_CFLAGS=""
 GTK4_LIBS=""
-if test "x$enable_gtk4" = "xyes"; then
+if test "test_gtk4" = yes -a "x$enable_gtk4" = "xyes"; then
     if test "$with_system_cairo" = no; then
         add_warning 'Non-system cairo combined with gtk4 is assumed to cause trouble; proceed at your own risk.'
     fi
-    : ${with_system_cairo:=yes}
     PKG_CHECK_MODULES(GTK4, gtk4 gmodule-no-export-2.0 glib-2.0 >= 2.38 cairo atk)
     GTK4_CFLAGS=$(printf '%s' "$GTK4_CFLAGS" | sed -e "s/-I/${ISYSTEM?}/g")
     GTK4_CFLAGS="$GTK4_CFLAGS -DGDK_DISABLE_DEPRECATED -DGTK_DISABLE_DEPRECATED"
@@ -11723,30 +11730,13 @@ if test "$enable_split_opt_features" = "yes"; then
 fi
 AC_SUBST(SPLIT_OPT_FEATURES)
 
-if test $_os = Darwin -o $_os = WINNT -o $_os = iOS; then
-    if test "$enable_cairo_canvas" = yes; then
-        AC_MSG_ERROR([The cairo canvas should not be used for this platform])
-    fi
-    enable_cairo_canvas=no
-elif test -z "$enable_cairo_canvas"; then
-    enable_cairo_canvas=yes
-fi
-
-ENABLE_CAIRO_CANVAS=""
-if test "$enable_cairo_canvas" = "yes"; then
-    test_cairo=yes
-    ENABLE_CAIRO_CANVAS="TRUE"
-    AC_DEFINE(ENABLE_CAIRO_CANVAS)
-fi
-AC_SUBST(ENABLE_CAIRO_CANVAS)
-
 dnl ===================================================================
 dnl Check whether the GStreamer libraries are available.
 dnl ===================================================================
 
 ENABLE_GSTREAMER_1_0=""
 
-if test "$build_gstreamer_1_0" = "yes"; then
+if test "$test_gstreamer_1_0" = yes; then
 
     AC_MSG_CHECKING([whether to enable the GStreamer 1.0 avmedia backend])
     if test "$enable_avmedia" = yes -a "$enable_gstreamer_1_0" != no; then
@@ -12729,7 +12719,7 @@ then
 the root of your Qt installation by exporting QT5DIR before running "configure".])
     fi
 
-    if test "$build_gstreamer_1_0" = "yes"; then
+    if test "$test_gstreamer_1_0" = yes; then
         PKG_CHECK_MODULES(QT5_GOBJECT,[gobject-2.0], [
                 QT5_HAVE_GOBJECT=1
                 AC_DEFINE(QT5_HAVE_GOBJECT)
@@ -13114,15 +13104,9 @@ dnl ===================================================================
 dnl Test whether to build cairo or rely on the system version
 dnl ===================================================================
 
-if test "$USING_X11" = TRUE; then
-    # Used in vcl/Library_vclplug_gen.mk
-    test_cairo=yes
-fi
-
 if test "$test_cairo" = "yes"; then
     AC_MSG_CHECKING([whether to use the system cairo])
 
-    : ${with_system_cairo:=$with_system_libs}
     if test "$with_system_cairo" = "yes"; then
         SYSTEM_CAIRO=TRUE
         AC_MSG_RESULT([yes])
@@ -13145,16 +13129,20 @@ if test "$test_cairo" = "yes"; then
             AC_LANG_POP([C])
         fi
     else
-        SYSTEM_CAIRO=
         AC_MSG_RESULT([no])
-
         BUILD_TYPE="$BUILD_TYPE CAIRO"
     fi
+
+    if test "$enable_cairo_canvas" != no; then
+        AC_DEFINE(ENABLE_CAIRO_CANVAS)
+        ENABLE_CAIRO_CANVAS=TRUE
+    fi
 fi
 
-AC_SUBST(SYSTEM_CAIRO)
 AC_SUBST(CAIRO_CFLAGS)
 AC_SUBST(CAIRO_LIBS)
+AC_SUBST(ENABLE_CAIRO_CANVAS)
+AC_SUBST(SYSTEM_CAIRO)
 
 dnl ===================================================================
 dnl Test whether to use avahi
diff --git a/desktop/source/lib/init.cxx b/desktop/source/lib/init.cxx
index 8df015866484..77fb9e4baecc 100644
--- a/desktop/source/lib/init.cxx
+++ b/desktop/source/lib/init.cxx
@@ -3161,7 +3161,7 @@ static void doc_paintTile(LibreOfficeKitDocument* pThis,
         return;
     }
 
-#if defined(UNX) && !defined(MACOSX) && !defined(ENABLE_HEADLESS)
+#if defined(UNX) && !defined(MACOSX)
 
     // Painting of zoomed or HiDPI spreadsheets is special, we actually draw everything at 100%,
     // and only set cairo's (or CoreGraphic's, in the iOS case) scale factor accordingly, so that
diff --git a/distro-configs/LibreOfficeAndroid.conf b/distro-configs/LibreOfficeAndroid.conf
index 3ff76a8d60a9..c95bef658956 100644
--- a/distro-configs/LibreOfficeAndroid.conf
+++ b/distro-configs/LibreOfficeAndroid.conf
@@ -1,8 +1,4 @@
 --host=arm-linux-androideabi
---disable-cairo-canvas
---disable-cups
---disable-gstreamer-1-0
---disable-randr
 --without-export-validation
 --without-helppack-integration
 --without-junit
diff --git a/distro-configs/LibreOfficeAndroidAarch64.conf b/distro-configs/LibreOfficeAndroidAarch64.conf
index bfc948c021f7..538ae3b07975 100644
--- a/distro-configs/LibreOfficeAndroidAarch64.conf
+++ b/distro-configs/LibreOfficeAndroidAarch64.conf
@@ -1,8 +1,4 @@
 --host=aarch64-linux-android
---disable-cairo-canvas
---disable-cups
---disable-gstreamer-1-0
---disable-randr
 --without-export-validation
 --without-helppack-integration
 --without-junit
diff --git a/distro-configs/LibreOfficeAndroidX86.conf b/distro-configs/LibreOfficeAndroidX86.conf
index 8fc92786c5e7..49f4b4729971 100644
--- a/distro-configs/LibreOfficeAndroidX86.conf
+++ b/distro-configs/LibreOfficeAndroidX86.conf
@@ -1,8 +1,4 @@
 --host=i686-linux-android
---disable-cairo-canvas
---disable-cups
---disable-gstreamer-1-0
---disable-randr
 --without-export-validation
 --without-helppack-integration
 --without-junit
diff --git a/distro-configs/LibreOfficeAndroidX86_64.conf b/distro-configs/LibreOfficeAndroidX86_64.conf
index efbbdbb1e945..307fe3b38603 100644
--- a/distro-configs/LibreOfficeAndroidX86_64.conf
+++ b/distro-configs/LibreOfficeAndroidX86_64.conf
@@ -1,8 +1,4 @@
 --host=x86_64-linux-android
---disable-cairo-canvas
---disable-cups
---disable-gstreamer-1-0
---disable-randr
 --without-export-validation
 --without-helppack-integration
 --without-junit
diff --git a/vcl/Library_vcl.mk b/vcl/Library_vcl.mk
index 45861cf2271c..aed3ce9603da 100644
--- a/vcl/Library_vcl.mk
+++ b/vcl/Library_vcl.mk
@@ -512,7 +512,7 @@ vcl_headless_code= \
     $(if $(filter-out iOS,$(OS)), \
         vcl/headless/svpbmp \
         vcl/headless/svpgdi \
-        vcl/headless/svpdata \
+        $(if $(ENABLE_HEADLESS),vcl/headless/svpdata) \
         vcl/headless/CustomWidgetDraw \
     ) \
     vcl/headless/svpdummies \
diff --git a/vcl/source/app/salplug.cxx b/vcl/source/app/salplug.cxx
index 8179e0c95097..41a30c8ed5ec 100644
--- a/vcl/source/app/salplug.cxx
+++ b/vcl/source/app/salplug.cxx
@@ -46,10 +46,10 @@
 #include <android/androidinst.hxx>
 #endif
 
-#if !(defined _WIN32 || defined MACOSX)
 #if USING_X11
 #define DESKTOPDETECT
 #endif
+#if ENABLE_HEADLESS
 #define HEADLESS_VCLPLUG
 #endif
 
diff --git a/vcl/source/font/fontcache.cxx b/vcl/source/font/fontcache.cxx
index 4ed38bc70153..8b6730a81447 100644
--- a/vcl/source/font/fontcache.cxx
+++ b/vcl/source/font/fontcache.cxx
@@ -24,10 +24,6 @@
 #include <PhysicalFontFamily.hxx>
 #include <sal/log.hxx>
 
-#if !(defined(_WIN32) || defined(MACOSX) || defined(IOS))
-#include <unx/glyphcache.hxx>
-#endif
-
 size_t ImplFontCache::IFSD_Hash::operator()( const FontSelectPattern& rFSD ) const
 {
     return rFSD.hashCode();
diff --git a/vcl/source/opengl/OpenGLHelper.cxx b/vcl/source/opengl/OpenGLHelper.cxx
index ee2047548103..b2f6e4a874e7 100644
--- a/vcl/source/opengl/OpenGLHelper.cxx
+++ b/vcl/source/opengl/OpenGLHelper.cxx
@@ -8,6 +8,7 @@
  */
 
 #include <vcl/opengl/OpenGLHelper.hxx>
+#include <config_vclplug.h>
 
 #include <osl/file.hxx>
 #include <rtl/bootstrap.hxx>
@@ -38,7 +39,7 @@
 #include <vcl/skia/SkiaHelper.hxx>
 #include <vcl/glxtestprocess.hxx>
 
-#if defined UNX && !defined MACOSX && !defined IOS && !defined ANDROID && !defined HAIKU
+#if USING_X11
 #include <opengl/x11/X11DeviceInfo.hxx>
 #elif defined (_WIN32)
 #include <opengl/win/WinDeviceInfo.hxx>
@@ -200,7 +201,7 @@ namespace
 
     OString getDeviceInfoString()
     {
-#if defined( SAL_UNX ) && !defined( MACOSX ) && !defined( IOS )&& !defined( ANDROID ) && !defined( HAIKU )
+#if USING_X11
         const X11OpenGLDeviceInfo aInfo;
         return aInfo.GetOS() +
             aInfo.GetOSRelease() +
@@ -762,7 +763,7 @@ bool OpenGLHelper::isDeviceDenylisted()
     {
         OpenGLZone aZone;
 
-#if defined UNX && !defined MACOSX && !defined IOS && !defined ANDROID && !defined HAIKU
+#if USING_X11
         X11OpenGLDeviceInfo aInfo;
         bDenylisted = aInfo.isDeviceBlocked();
         SAL_INFO("vcl.opengl", "denylisted: " << bDenylisted);
diff --git a/vcl/source/treelist/transfer2.cxx b/vcl/source/treelist/transfer2.cxx
index 0d43db107d9a..bc654bbb7975 100644
--- a/vcl/source/treelist/transfer2.cxx
+++ b/vcl/source/treelist/transfer2.cxx
@@ -17,7 +17,7 @@
  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  */
 
-#include <config_features.h>
+#include <config_vclplug.h>
 
 #include <osl/mutex.hxx>
 #include <sot/exchange.hxx>
@@ -498,7 +498,7 @@ Reference<XClipboard> GetSystemPrimarySelection()
     try
     {
         Reference<XComponentContext> xContext(comphelper::getProcessComponentContext());
-#if HAVE_FEATURE_X11
+#if USING_X11
         // A hack, making the primary selection available as an instance
         // of the SystemClipboard service on X11:
         Sequence< Any > args(1);
diff --git a/vcl/source/window/mouse.cxx b/vcl/source/window/mouse.cxx
index e57485927eed..d1b3590ed97b 100644
--- a/vcl/source/window/mouse.cxx
+++ b/vcl/source/window/mouse.cxx
@@ -18,8 +18,8 @@
  */
 
 
-#include <config_features.h>
 #include <config_feature_desktop.h>
+#include <config_vclplug.h>
 
 #include <tools/time.hxx>
 
@@ -745,7 +745,7 @@ Reference< css::datatransfer::dnd::XDragSource > Window::GetDragSource()
                     aDropTargetSN = "com.sun.star.datatransfer.dnd.OleDropTarget";
                     aDragSourceAL[ 1 ] <<= static_cast<sal_uInt64>( reinterpret_cast<sal_IntPtr>(pEnvData->mpNSView) );
                     aDropTargetAL[ 0 ] <<= static_cast<sal_uInt64>( reinterpret_cast<sal_IntPtr>(pEnvData->mpNSView) );
-#elif HAVE_FEATURE_X11
+#elif USING_X11
                     aDragSourceSN = "com.sun.star.datatransfer.dnd.X11DragSource";
                     aDropTargetSN = "com.sun.star.datatransfer.dnd.X11DropTarget";