Major optimization of C/C++ dependency scanning.
Now only the dependencies for the file where the dependencies actually may have changed are rescanned, before that this was done for all source files even if only one source file had changed. This reduces e.g. on my machine the time for scanning the dependencies of kdelibs/khtml/ when only one file (khtml_global.cpp) has changed from around 7.5 seconds to 1.2 seconds. The tests succeed, it does what I expected it to do on kdelibs, and Brad also reviewed the patch, so I think it should be ok. Alex