Drop HAVE_GCC_ATTRIBUTE_WARN_UNUSED_STL

For one, loplugin:unusedvariablecheck does not merely check for unused variables
with types from the standard library since
fe2164949b38a7f73883dbdcb3271b94e5c81744 "teach unusedvariablecheck plugin about
SfxPoolItem subclasses", so disabling loplugin:unusedvariablecheck based on
HAVE_GCC_ATTRIBUTE_WARN_UNUSED_STL is wrong.

For another, I have seen no standard library implementation that decorates its
types with such "warn-if-unused" attributes, and
<http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0600r0.pdf>
"[[nodiscard]] in the Library" (which proposes to add the corresponding C++17
attribute to just a few select functions and no types at all) makes it appear
unlikely that will happen.

Change-Id: I0a7759e1caf3e3137057c9689080948a4d6747e0

1 files changed, 0 insertions, 15 deletions

diff --git a/configure.ac b/configure.ac
index 8a8c6a5be5b4..fdd9c005fc1a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -5904,21 +5904,6 @@ if test "$GCC" = "yes" -o "$COM_IS_CLANG" = TRUE; then
         ], [AC_MSG_RESULT([no])])
     AC_LANG_POP([C++])
 
-    AC_MSG_CHECKING([whether STL uses __attribute__((warn_unused))])
-    AC_LANG_PUSH([C++])
-    save_CXXFLAGS=$CXXFLAGS
-    CXXFLAGS="$CXXFLAGS -Werror -Wunused"
-    AC_COMPILE_IFELSE([AC_LANG_SOURCE([
-            #include <string>
-            void f() { std::string s; }
-        ])], [
-            AC_MSG_RESULT([no])
-        ], [
-            AC_DEFINE([HAVE_GCC_ATTRIBUTE_WARN_UNUSED_STL],[1])
-            AC_MSG_RESULT([yes])])
-    CXXFLAGS=$save_CXXFLAGS
-    AC_LANG_POP([C++])
-
     AC_MSG_CHECKING([whether $CXX supports __attribute__((warn_unused))])
     AC_LANG_PUSH([C++])
     save_CXXFLAGS=$CXXFLAGS