tmp/JSDocument.o: In function `.L948':
JSDocument.cpp:(.text+0x2737): undefined reference to `WebCore::Document::defaultView() const'
Is it still reproducible?
BTW "P5 is not used for WebKit bugs. WebKit shares its Bugzilla with other projects who might use it, that's why it's still there." [http://webkit.org/quality/bugpriorities.html]
This build issue has been open for 8 months now without any other duplicates or comments so closing it WORKSFORME.
For the record, build issues are usually handled within a few days. If it persists, your best bet is:
1) do a clean build (the undefined symbol error are usually when make does not re-compile everything as it should do). You may checkout the sources again to avoid unfortunate changes you may have made.
2) if 1) does not work, ask on the webkit-dev mailing list providing as much information as possible.