* configure.ac (WARN_CFLAGS, WARN_CXXFLAGS): Do not include options
that Clang does not support.
---
configure.ac | 18 +++++++++++++++++-
1 file changed, 17 insertions(+), 1 deletion(-)
diff --git a/configure.ac b/configure.ac
index 4cc9ef9..651fa13 100644
--- a/configure.ac
+++ b/configure.ac
@@ -72,6 +72,18 @@ if test "$enable_gcc_warnings" = yes; then
-Wshadow -Wstrict-prototypes'
warn_cxx='-Wnoexcept'
AC_LANG_PUSH([C])
+ # Clang supports many of GCC's -W options, but only issues warnings
+ # on the ones it does not recognize. In that case, gl_WARN_ADD
+ # thinks the option is supported, and unknown options are then added
+ # to CFLAGS. But then, when -Werror is added in the test suite for
+ # instance, the warning about the unknown option turns into an
+ # error.
+ #
+ # This should be addressed by gnulib's gl_WARN_ADD, but in the
+ # meanwhile, turn warnings about unknown options into errors in
+ # CFLAGS, and restore CFLAGS after the tests.
+ save_CFLAGS=$CFLAGS
+ gl_WARN_ADD([-Werror=unknown-warning-option], [CFLAGS])
for i in $warn_common $warn_c;
do
gl_WARN_ADD([$i], [WARN_CFLAGS])
@@ -80,19 +92,23 @@ if test "$enable_gcc_warnings" = yes; then
# Warnings for the test suite only.
gl_WARN_ADD([-Wundef], [WARN_CFLAGS_TEST])
gl_WARN_ADD([-pedantic], [WARN_CFLAGS_TEST])
+ CFLAGS=$save_CFLAGS
AC_LANG_POP([C])
AC_LANG_PUSH([C++])
+ save_CXXFLAGS=$CXXFLAGS
+ gl_WARN_ADD([-Werror=unknown-warning-option], [CXXFLAGS])
for i in $warn_common $warn_cxx;
do
gl_WARN_ADD([$i], [WARN_CXXFLAGS])
done
- gl_WARN_ADD([ -Wzero-as-null-pointer-constant], [WARN_CXXFLAGS],
+ gl_WARN_ADD([-Wzero-as-null-pointer-constant], [WARN_CXXFLAGS],
[AC_LANG_PROGRAM([], [nullptr])])
gl_WARN_ADD([-Werror], [WERROR_CXXFLAGS])
# Warnings for the test suite only.
gl_WARN_ADD([-Wundef], [WARN_CXXFLAGS_TEST])
gl_WARN_ADD([-pedantic], [WARN_CXXFLAGS_TEST])
+ CXXFLAGS=$save_CXXFLAGS
AC_LANG_POP([C++])
fi
--
1.7.12.2
