[gtkmm/gtkmm-3-24] Meson build: Fix versioning on macOS

[Kjell Ahlstedt <kjellahl src gnome org>]

commit 92909865f6aa157fb0c6440a999e494479465b5c
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Thu Oct 1 11:21:19 2020 +0200

    Meson build: Fix versioning on macOS
    
    See libsigcplusplus, pull request 65

 gdk/gdkmm/meson.build | 4 +++-
 gtk/gtkmm/meson.build | 4 +++-
 meson.build           | 7 ++++++-
 3 files changed, 12 insertions(+), 3 deletions(-)
---
diff --git a/gdk/gdkmm/meson.build b/gdk/gdkmm/meson.build
index 8d9e74f3..afccaea0 100644
--- a/gdk/gdkmm/meson.build
+++ b/gdk/gdkmm/meson.build
@@ -4,7 +4,7 @@
 #        generate_binding_py, m4_files, gtkmm_libversion, install_includedir,
 #        python3, gdkmm_rc, dummy_header_py, gmmproc_dir, build_shared_libs_directly,
 #        build_deprecated_api, gmmproc_extra_m4_dirs, is_host_windows,
-#        gdkmm_extra_gendef_cpp_args, gdkmm_libname
+#        gdkmm_extra_gendef_cpp_args, gdkmm_libname, macos_darwin_versions
 # Output: gdkmm_hg_ccg_basenames, gdkmm_extra_h_files, built_files_root,
 #         gdkmm_built_h_file_targets, gdkmm_used_built_h_file_targets, gdkmm_dep
 
@@ -229,6 +229,7 @@ if build_shared_libs_directly
     include_directories: extra_include_dirs,
     cpp_args: gdkmm_cpp_args,
     version: gtkmm_libversion,
+    darwin_versions: macos_darwin_versions,
     dependencies: gdkmm_build_dep,
     install: true,
   )
@@ -260,6 +261,7 @@ else
   gdkmm_library = library(gdkmm_libname, extra_gdkmm_objects,
     objects: gdk_int_lib.extract_all_objects(),
     version: gtkmm_libversion,
+    darwin_versions: macos_darwin_versions,
     dependencies: gdkmm_build_dep,
     link_depends: gdkmm_def,
     link_args: gdkmm_extra_link_args,
diff --git a/gtk/gtkmm/meson.build b/gtk/gtkmm/meson.build
index 4f300920..ab96a221 100644
--- a/gtk/gtkmm/meson.build
+++ b/gtk/gtkmm/meson.build
@@ -5,7 +5,7 @@
 #        python3, gtkmm_rc, dummy_header_py, gmmproc_dir, build_shared_libs_directly,
 #        build_deprecated_api, build_x11_api, gmmproc_extra_m4_dirs, is_host_windows,
 #        gdkmm_library, gdkmm_used_built_h_file_targets, gtkmm_extra_gendef_cpp_args,
-#        gtkmm_libname
+#        gtkmm_libname, macos_darwin_versions
 # Output: gtkmm_hg_ccg_basenames, gtkmm_extra_h_files, built_files_root,
 #         gtkmm_built_h_file_targets, gtkmm_dep
 
@@ -495,6 +495,7 @@ if build_shared_libs_directly
     include_directories: extra_include_dirs,
     cpp_args: gtkmm_cpp_args,
     version: gtkmm_libversion,
+    darwin_versions: macos_darwin_versions,
     dependencies: gtkmm_build_dep,
     link_with: gdkmm_library,
     install: true,
@@ -528,6 +529,7 @@ else
   gtkmm_library = library(gtkmm_libname, extra_gtkmm_objects,
     objects: gtk_int_lib.extract_all_objects(),
     version: gtkmm_libversion,
+    darwin_versions: macos_darwin_versions,
     dependencies: gtkmm_build_dep,
     link_depends: gtkmm_def,
     link_args: gtkmm_extra_link_args,
diff --git a/meson.build b/meson.build
index 32eefb39..4da55cd8 100644
--- a/meson.build
+++ b/meson.build
@@ -31,7 +31,12 @@ libtool_soversion = [2, 0, 1]
 gtkmm_libversion = '@0@.@1@.@2@'.format(
   libtool_soversion[0] - libtool_soversion[2],
   libtool_soversion[2],
-  libtool_soversion[1])
+  libtool_soversion[1]
+)
+macos_darwin_versions = [
+  libtool_soversion[0] + 1,
+  '@0@.@1@'.format(libtool_soversion[0] + 1, libtool_soversion[1])
+]
 
 # Use these instead of meson.source_root() and meson.build_root() in subdirectories.
 # source_root() and build_root() are not useful, if this is a subproject.