meson: Add macOS libtool versioning for ABI compatibility

With this, the compatibility version and current version values in macOS
and iOS dylibs will match the values set by Autotools.

See: https://github.com/mesonbuild/meson/issues/1451

gio/meson.build

@@ -797,6 +797,7 @@ libgio = library('gio-2.0',
   objects : internal_objects,
   version : library_version,
   soversion : soversion,
+  darwin_versions : darwin_versions,
   install : true,
   include_directories : [configinc, gioinc],
   #  '$(gio_win32_res_ldflag)',