llvm-mirror/autoconf/m4/cxx_flag_check.m4
Richard Smith 91f9b50b1c configure: when performing a compiler feature test for a -Wno-foo flag, attempt
to use -Wfoo instead of -Wno-foo. This works around a bug in some versions of
gcc, where it will silently accept an unknown -Wno-foo option, but will
generate an error for a compile which uses -Wno-foo if that compile also
triggers any warnings.

llvm-svn: 174770
2013-02-08 22:55:10 +00:00

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AC_DEFUN([CXX_FLAG_CHECK],
[AC_SUBST($1, `$CXX -Werror patsubst($2, [^-Wno-], [-W]) -fsyntax-only -xc /dev/null 2>/dev/null && echo $2`)])