I got stuck with kdelibs yesterday. Today I first considered installing qt-copy, but then I found the problem. If I pass a CFLAGS value to make it overrides the CFLAGS determined by configure.
Now my Laptop is happily compiling kdelibs and I wait until it breaks the next time :-). Unfortunately there is no distcc environment at work so it will take some time. (No, I will not update my work-station to 5.1)
BTW this is the first entry posted from work.