external/icu: Fix intermittent cross build failure

The ICU build for Android sometimes failed
as follows:

> ICU for C/C++ 72.1 is ready to be built.
> === Important Notes: ===
> Data Packaging: static
>  This means: ICU data will be stored in a static library.
>  To locate data: ICU will use the linked data library. If linked with the stub library located in stubdata/, the application can use udata_setCommonData() or set a data path to override.
> Building ICU: Use a GNU make such as /usr/bin/gmake to build ICU.
> checking the version of "/usr/bin/gmake"... gmake[2]: Entering directory '/home/michi/development/git/libreoffice-WORKTREE-for-android-x86/workdir/UnpackedTarball/icu/source'
> 4.3 (we wanted at least 3.80)
> gmake[2]: Leaving directory '/home/michi/development/git/libreoffice-WORKTREE-for-android-x86/workdir/UnpackedTarball/icu/source'
> ok
> ## Note: you have disabled ICU's tools. This ICU cannot build its own data or tests.
> ## Expect build failures in the 'data', 'test', and other directories.
> icudefs.mk:328: @cross_mixed_buildroot@/config/icucross.mk: No such file or directory
> make[2]: *** No rule to make target '@cross_mixed_buildroot@/config/icucross.mk'.  Stop.
> make[1]: *** [/home/michi/development/git/libreoffice-WORKTREE-for-android-x86/external/icu/ExternalProject_icu.mk:68: /home/michi/development/git/libreoffice-WORKTREE-for-android-x86/workdir/ExternalProject/icu/build] Error 1
> make: *** [Makefile:289: build] Error 2

config.log showed that instead of the
`cross_mixed_buildroot` and `cross_unix_buildroot`
configure variables introduced instead of
`cross_buildroot` in

    commit 7f16cabf00daa30e9284d2fb2494bd341352c25e
    Date:   Thu Oct 1 11:20:50 2020 +0200

        icu: fix Windows Cygwin cross build

, only the latter was set.

While that commit also added a call to autoconf
to update `configure` from the patched `configure.ac`,
autoconf would leave the old version in place if
the timestamp of `configure` was newer than that of
`configure.ac` after unpacking the tarball.

Call autoconf with the `-f` param to force the update.

Do the same for another autoconf invocation that was
added in

    commit 6c94958e56fcbacb8e1f689550a60034b074857c
    Date:   Fri Jul 17 22:25:01 2020 +0200

        icu: fix Windows Arm64 build

Change-Id: I5685ebce13e2950a4dc8f1dec75c4aed18d584f6
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/145043
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>
(cherry picked from commit 8ecc8ebf2b94615928449f431884525b605fbfa5)
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/145005
Reviewed-by: Michael Stahl <michael.stahl@allotropia.de>

1 files changed, 2 insertions, 2 deletions

diff --git a/external/icu/ExternalProject_icu.mk b/external/icu/ExternalProject_icu.mk
index d677016f9677..1fd0600fe5c6 100644
--- a/external/icu/ExternalProject_icu.mk
+++ b/external/icu/ExternalProject_icu.mk
@@ -20,7 +20,7 @@ ifeq ($(OS),WNT)
 $(call gb_ExternalProject_get_state_target,icu,build) :
 	$(call gb_Trace_StartRange,icu,EXTERNAL)
 	$(call gb_ExternalProject_run,build,\
-		autoconf \
+		autoconf -f \
 		&& export LIB="$(ILIB)" PYTHONWARNINGS="default" \
 			gb_ICU_XFLAGS="-FS $(SOLARINC) $(gb_DEBUGINFO_FLAGS) $(if $(MSVC_USE_DEBUG_RUNTIME),-MDd,-MD -Gy)" \
 		&& CFLAGS="$${gb_ICU_XFLAGS}" CPPFLAGS="$(SOLARINC)" CXXFLAGS="$${gb_ICU_XFLAGS}" \
@@ -66,7 +66,7 @@ icu_LDFLAGS:=" \
 $(call gb_ExternalProject_get_state_target,icu,build) :
 	$(call gb_Trace_StartRange,icu,EXTERNAL)
 	$(call gb_ExternalProject_run,build,\
-		autoconf && \
+		autoconf -f && \
 		CPPFLAGS=$(icu_CPPFLAGS) CFLAGS=$(icu_CFLAGS) \
 		CXXFLAGS=$(icu_CXXFLAGS) LDFLAGS=$(icu_LDFLAGS) \
 		PYTHONWARNINGS="default" \