Doxyfile: Remove options to avoid warnings from doxygens without clang support
Doxyfile: Remove options to avoid warnings from doxygens without clang support

MatzeB/libfirm,libfirm/libfirm,libfirm/libfirm,libfirm/libfirm,libfirm/libfirm,libfirm/libfirm,MatzeB/libfirm,MatzeB/libfirm,MatzeB/libfirm,MatzeB/libfirm,MatzeB/libfirm,MatzeB/libfirm