giscanner: undef "GLIB_VERSION_{MAX_ALLOWED,MIN_REQUIRED}" macros in generated C file

When g-ir-scanner is used by another project, than that project might
have the GLIB_VERSION_* macros defined. This is useful to ensure that
only intended glib API is used.

The project might then also pass the CFLAGS to g-ir-scanner, without
filtering those defines out. This can lead to compiler warnings.

For example, NetworkManager sets the version macros to GLIB_VERSION_2_40
and thus gets these warnings

  /NetworkManager/tmp-introspect66917zc4/NM-1.0.c: In function ‘dump_object_type’:
  /NetworkManager/tmp-introspect66917zc4/NM-1.0.c:252:13: warning: Not available before 2.70
    252 |   if (G_TYPE_IS_FINAL (type))
        |             ^~~~~~~~~~~~~~~~~
  /NetworkManager/tmp-introspect66917zc4/NM-1.0.c: In function ‘dump_fundamental_type’:
  /NetworkManager/tmp-introspect66917zc4/NM-1.0.c:370:13: warning: Not available before 2.70
    370 |   if (G_TYPE_IS_FINAL (type))
        |             ^~~~~~~~~~~~~~~~~

But these warnings are not correct. The installed g-ir-scanner knows for which
glib version to generate code. Undefine the macros to avoid the warning.

0 files changed, 0 insertions, 0 deletions