GLib deprecated the GValueArray type without providing an ABI
compatible replacement. Thus we need to disable dreprecation
warnings
../../src/virt-viewer-auth.c: In function 'virt_viewer_auth_vnc_credentials':
../../src/virt-viewer-auth.c:112:9: error: 'g_value_array_get_nth' is deprecated (declared at /usr/include/glib-2.0/gobject/gvaluearray.h:65): Use 'g_array_index' instead [-Werror=deprecated-declarations]
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.
