[gobject-introspection/th/undef-glib-version] giscanner: undef "GLIB_VERSION_{MAX_ALLOWED, MIN_REQUIRED}" macros in generated C file

[Thomas Haller <thaller src gnome org>]

commit 8cddb5d2d909eb66b35ec808235a26ad620ad0fc
Author: Thomas Haller <thaller redhat com>
Date:   Thu Apr 7 11:17:52 2022 +0200

    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.

 giscanner/dumper.py | 4 ++++
 1 file changed, 4 insertions(+)
---
diff --git a/giscanner/dumper.py b/giscanner/dumper.py
index 22afd61e..74a494b8 100644
--- a/giscanner/dumper.py
+++ b/giscanner/dumper.py
@@ -34,6 +34,10 @@ from .ccompiler import CCompiler
 # we want to introspect, in order to call its get_type functions.
 
 _PROGRAM_TEMPLATE = """/* This file is generated, do not edit */
+
+#undef GLIB_VERSION_MIN_REQUIRED
+#undef GLIB_VERSION_MAX_ALLOWED
+
 #include <glib.h>
 #include <string.h>
 #include <stdlib.h>