Compiler range to build root6.02.05

I built root6.02.05 successfully using g++ (GCC) 4.8.3 20140911 on fedora 20 3.19.5-100.fc20.x86_64.
However when I upgraded my machine to gcc (GCC) 4.9.2 on Fedora 21 I am unable to rebuild it.
The failure is in
Generating dictionary core/base/src/G__Core.cxx…
core/utils/src/rootcling_tmp -f core/base/src/G__Core.cxx -s lib/ -c

*** Error in `core/utils/src/rootcling_tmp’: free(): invalid pointer: 0x00007ffe99a973f8 ***

I can also report that this has been fixed in root6.02.10 which builds successfully with gcc 4.9.2
so only the documentation of the gcc range for this build needs to be changed.

Did you clean completely your build area after upgrading the compiler?

I did make clean and ran ./configure on the new system. Was that not sufficient?
It was not. After running make distclean the build succeeded.
Sorry for the false report.