Forwarding headers for WebCore should be generated based on WebCore sources instead of WebKit2.

Rubber-stamped by Andras Becsi.

* DerivedSources.pro:
* WebCore.pro: Add platform/mac/DisplaySleepDisabler.cpp to SOURCES.

Source/WebKit2: [Qt][Mac] Buildfix after r95513.

Rubber-stamped by Andras Becsi.

* Scripts/generate-forwarding-headers.pl: Add mm file supporting.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@95542 268f45cc-cd09-0410-ab3c-d52691b4dbfc