build: add -Wconditionally-supported to strict_warn [PR64867]

The PR (which isn't resolved by this commit) pointed out to me that GCC
should build with -Wconditionally-supported to support bootstrapping with a
C++11 compiler that makes different choices.

	PR c++/64867

gcc/ChangeLog:

	* configure.ac (strict_warn): Add -Wconditionally-supported.
	* configure: Regenerate.

diff --git a/gcc/configure b/gcc/configure
index 61b3cedbe693ea02692590aa39bbd5bfe3e0fe91..921aad607127969da752d95c908feba79dea822b 100755 (executable)
--- a/gcc/configure
+++ b/gcc/configure
@@ -7215,7 +7215,7 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
 
 strict_warn=
 save_CXXFLAGS="$CXXFLAGS"
-for real_option in -Wmissing-format-attribute -Woverloaded-virtual; do
+for real_option in -Wmissing-format-attribute -Wconditionally-supported -Woverloaded-virtual; do
   # Do the check with the no- prefix removed since gcc silently
   # accepts any -Wno-* option on purpose
   case $real_option in

diff --git a/gcc/configure.ac b/gcc/configure.ac
index 5efbf11793cf224b40d42132741e5bfa0754389e..b91f54ce05bcd363416c34c3a901c94148b68b1b 100644 (file)
--- a/gcc/configure.ac
+++ b/gcc/configure.ac
@@ -580,7 +580,7 @@ ACX_PROG_CC_WARNING_OPTS(
        m4_quote(m4_do([-Wstrict-prototypes -Wmissing-prototypes ],
                       [])), [c_loose_warn])
 ACX_PROG_CXX_WARNING_OPTS(
-       m4_quote(m4_do([-Wmissing-format-attribute ],
+       m4_quote(m4_do([-Wmissing-format-attribute ], [-Wconditionally-supported ],
                       [-Woverloaded-virtual])), [strict_warn])
 ACX_PROG_CC_WARNING_OPTS(
        m4_quote(m4_do([-Wold-style-definition -Wc++-compat])), [c_strict_warn])