Fix copied from libvirt, commit by Eric Blake.
glibc 2.15 (on Fedora 17) coupled with explicit disabling of
optimization during development dies a painful death:
/usr/include/features.h:314:4: error: #warning _FORTIFY_SOURCE requires compiling with optimization (-O) [-Werror=cpp]
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.
The API design of SLIRP means that it is not practical to use
the -Waggregate-return warning flag. Disable this flag in the
(unlikely) scenario where SLIRP is actually requested at build
time
* m4/manywarnings.m4m, m4/warnings.m4: Import GNULIB warnings
modules
* m4/spice-compile-warnings.m4: Define SPICE_COMPILE_WARNINGS
* configure.ac: Replace compile warning check with a call to
SPICE_COMPILE_WARNINGS
* client/Makefile.am: Use WARN_CXXFLAGS instead of WARN_CFLAGS
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
