[glibmm] Meson build: Fix versioning on macOS for libglibmm_generate_extra_defs

[Kjell Ahlstedt <kjellahl src gnome org>]

commit 68773521cf8350cd0a6bf21a5170d25ccf47c18b
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Thu Oct 1 10:52:30 2020 +0200

    Meson build: Fix versioning on macOS for libglibmm_generate_extra_defs

 tools/extra_defs_gen/meson.build | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
---
diff --git a/tools/extra_defs_gen/meson.build b/tools/extra_defs_gen/meson.build
index 5080b7d5..0cc3cfba 100644
--- a/tools/extra_defs_gen/meson.build
+++ b/tools/extra_defs_gen/meson.build
@@ -1,13 +1,15 @@
 # tools/extra_defs_gen
 
 # Input: glibmm_build_dep, giomm_build_dep, glibmm_api_version,
-#        glibmm_libversion, glibmm_pcname, msvc14x_toolset_ver
+#        glibmm_libversion, glibmm_pcname, msvc14x_toolset_ver,
+#        macos_darwin_versions
 # Output: -
 
 glibmm_generate_extra_defs_library = library(
   'glibmm_generate_extra_defs' + msvc14x_toolset_ver + '-' + glibmm_api_version,
   'generate_extra_defs.cc',
   version: glibmm_libversion,
+  darwin_versions: macos_darwin_versions,
   cpp_args: '-DGLIBMM_GEN_EXTRA_DEFS_BUILD',
   dependencies: glibmm_build_dep,
   install: true,