[atkmm/atkmm-2-28] Meson build: Fix versioning on macOS

[Kjell Ahlstedt <kjellahl src gnome org>]

commit f84848af1a44bee110a7908c17b2b63dbb3fdfe7
Author: Kjell Ahlstedt <kjellahlstedt gmail com>
Date:   Thu Oct 1 09:59:59 2020 +0200

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

 atk/atkmm/meson.build | 4 +++-
 meson.build           | 7 ++++++-
 2 files changed, 9 insertions(+), 2 deletions(-)
---
diff --git a/atk/atkmm/meson.build b/atk/atkmm/meson.build
index c98bb36..4d4acfe 100644
--- a/atk/atkmm/meson.build
+++ b/atk/atkmm/meson.build
@@ -3,7 +3,7 @@
 # Input: atkmm_build_dep, atkmm_pcname, maintainer_mode, project_source_root,
 #        generate_binding_py, m4_files, atkmm_libversion, install_includedir,
 #        python3, atkmm_rc, dummy_header_py, gmmproc_dir, build_shared_libs_directly,
-#        msvc14x_toolset_ver
+#        msvc14x_toolset_ver, macos_darwin_versions
 # Output: hg_ccg_basenames, extra_h_files, built_h_file_targets, built_files_root,
 #         atkmm_dep
 
@@ -201,6 +201,7 @@ if build_shared_libs_directly
     include_directories: extra_include_dirs,
     cpp_args: atkmm_cpp_args,
     version: atkmm_libversion,
+    darwin_versions: macos_darwin_versions,
     dependencies: atkmm_build_dep,
     install: true,
   )
@@ -232,6 +233,7 @@ else
   atkmm_library = library(atkmm_libname, extra_atkmm_objects,
     objects: atk_int_lib.extract_all_objects(),
     version: atkmm_libversion,
+    darwin_versions: macos_darwin_versions,
     dependencies: atkmm_build_dep,
     link_depends: atkmm_def,
     link_args: atkmm_extra_link_args,
diff --git a/meson.build b/meson.build
index c81e507..61d3a12 100644
--- a/meson.build
+++ b/meson.build
@@ -29,7 +29,12 @@ libtool_soversion = [2, 0, 1]
 atkmm_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.