autoconf: set all __STDC_*_MACROS

Analogous to previous commit(s), with a minor detail - here we set the
macros when building both C and C++ sources.

Resolving that is a more challenging task that we'll sort out another
day.

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Eric Engestrom <eric.engestrom@imgtec.com>
Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
1 file changed