Re: [libvirt] [libvirt-glib] build: allow building with newer glibc-headers and -O0

Commit log and autoconf snippet written by Eric Blake for libvirt. glibc 2.15 (on Fedora 17) coupled with explicit disabling of optimization during development dies a painful death: In file included from /usr/include/limits.h:27:0, from /usr/lib/gcc/x86_64-redhat-linux/4.7.0/include/limits.h:169,. from /usr/lib/gcc/x86_64-redhat-linux/4.7.0/include/syslimits.h:7, from /usr/lib/gcc/x86_64-redhat-linux/4.7.0/include/limits.h:34, from util/bitmap.c:26: /usr/include/features.h:314:4: error: #warning _FORTIFY_SOURCE requires compiling with optimization (-O) [-Werror=cpp] cc1: all warnings being treated as errors Work around this by only conditionally defining _FORTIFY_SOURCE, in the case where glibc can actually use it. The trick is using AH_VERBATIM instead of AC_DEFINE. * m4/virt-compile-warnings.m4 (LIBOSINFO_COMPILE_WARNINGS): Squelch _FORTIFY_SOURCE when needed to avoid glibc #warnings. --- m4/virt-compile-warnings.m4 | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)