Fix macOS builder to set up `mutool_lib` in `setup_extra` rather than overriding `setup_paths`, which was causing issues.

builders/macosx-builder.py

@@ -359,11 +359,10 @@ class MacOSXBuilder(Builder):
         qt_library_path = QCoreApplication.libraryPaths()[0]
         return os.path.join(os.path.dirname(qt_library_path), 'translations')
 
-    def setup_paths(self):
+    def setup_extra(self):
         """
         Extra setup to run
         """
-        super().setup_paths()
         if hasattr(self, 'mutool_exe'):
             self.mutool_lib = os.path.abspath(
                 os.path.join(os.path.dirname(self.mutool_exe), '..', 'lib', 'libjbig2dec.0.dylib'))