meson: use correct module file extension on macOS

GModule requires the .so file extension on macOS for historic reasons.
However Meson defaults to .dylib for modules, so we need to override
it to get the correct extension.

Fixes #3645.

meson.build

@@ -84,6 +84,13 @@ gtk_library_version = '1.@0@.@1@'.format(gtk_binary_age - gtk_interface_age, gtk
 
 gtk_api_version = '4.0'
 
+module_suffix = []
+# GModule requires file extension to be .so, not .dylib on Mac.
+# https://gitlab.gnome.org/GNOME/glib/issues/520
+if ['darwin', 'ios'].contains(host_machine.system())
+  module_suffix = 'so'
+endif
+
 x11_enabled      = get_option('x11-backend')
 wayland_enabled  = get_option('wayland-backend')
 broadway_enabled = get_option('broadway-backend')

modules/media/meson.build

@@ -35,6 +35,7 @@ if ffmpeg_found
     sources: 'gtkffmediafile.c',
     c_args: extra_c_args,
     dependencies: [ libgtk_dep, ffmpeg_deps ],
+    name_suffix: module_suffix,
     install_dir: media_install_dir,
     install: true,
   )
@@ -56,6 +57,7 @@ if gstplayer_dep.found() and gstgl_dep.found()
     ],
     c_args: extra_c_args,
     dependencies: [ libm, libgtk_dep, gstplayer_dep, gstgl_dep ],
+    name_suffix: module_suffix,
     install_dir: media_install_dir,
     install: true,
   )

modules/printbackends/meson.build

@@ -22,6 +22,7 @@ if cups_dep.found()
     ],
     c_args: printbackends_args,
     dependencies: [libgtk_dep, cups_dep, colord_dep],
+    name_suffix: module_suffix,
     install_dir: printbackends_install_dir,
     install: true,
   )
@@ -32,6 +33,7 @@ else
     sources: 'gtkprintbackendlpr.c',
     c_args: printbackends_args,
     dependencies: libgtk_dep,
+    name_suffix: module_suffix,
     install_dir: printbackends_install_dir,
     install: true,
   )
@@ -49,6 +51,7 @@ if rest_dep.found() and json_glib_dep.found()
     ],
     c_args: printbackends_args,
     dependencies: [ libgtk_dep, rest_dep, json_glib_dep ],
+    name_suffix: module_suffix,
     install_dir: printbackends_install_dir,
     install: true)
 endif
@@ -59,6 +62,7 @@ shared_module('printbackend-file',
   sources: 'gtkprintbackendfile.c',
   c_args: printbackends_args,
   dependencies: libgtk_dep,
+  name_suffix: module_suffix,
   install_dir: printbackends_install_dir,
   install: true,
 )