Add pyobjc to check_dependencies script

scripts/check_dependencies.py

@@ -41,6 +41,7 @@ except ImportError:
 
 IS_WIN = sys.platform.startswith('win')
 IS_LIN = sys.platform.startswith('lin')
+IS_MAC = sys.platform.startswith('dar')
 
 
 VERS = {
@@ -66,6 +67,11 @@ LINUX_MODULES = [
     'dbus',
 ]
 
+MACOSX_MODULES = [
+    'objc',
+    'AppKit'
+]
+
 
 MODULES = [
     'PyQt5',
@@ -234,6 +240,10 @@ def main():
         print('Checking for Linux specific modules...')
         for m in LINUX_MODULES:
             check_module(m)
+    elif IS_MAC:
+        print('Checking for Mac OS X specific modules...')
+        for m in MACOSX_MODULES:
+            check_module(m)
     verify_versions()
     print_qt_image_formats()
     print_enchant_backends_and_languages()