diff --git a/osx/build_app.sh b/osx/build_app.sh
index 7b7c0ee4..3e413efb 100755
--- a/osx/build_app.sh
+++ b/osx/build_app.sh
@@ -39,7 +39,7 @@ cp osx/conf.py meld/conf.py
 ${INSTROOT}/bin/python3 -c "import sys; print('\n'.join(sys.path))"
 
 PY_SITE_PACKAGES=$(~/gtk/inst/bin/python3 -c 'import site; print(site.getsitepackages()[0], end="")')
-/usr/local/bin/pip3 install distro pyobjc-core pyobjc-framework-Cocoa py2app --target $PY_SITE_PACKAGES
+/usr/local/bin/pip3 install --upgrade --force-reinstall distro pyobjc-core pyobjc-framework-Cocoa py2app six pygments --target $PY_SITE_PACKAGES
 
 glib-compile-schemas data
 ${INSTROOT}/bin/python3 setup_py2app.py build
diff --git a/setup_py2app.py b/setup_py2app.py
index 966d7df5..731f7116 100644
--- a/setup_py2app.py
+++ b/setup_py2app.py
@@ -7,6 +7,7 @@
 import site
 import meld.build_helpers
 import meld.conf
+import Foundation
 from setuptools import setup
 
 if sys.version_info[:2] < meld.conf.PYTHON_REQUIREMENT_TUPLE: