If you suspect a bug in the compiler (which this looks like it), find out which libXaw.so object has undefined .L91 symbol and file a bugreport in http://bugzilla.redhat.com/bugzilla/ with the details (gcc command line used to compile that object with .L91 undefined reference (use e.g. nm -u to find out), preprocessed source (add -save-temps to gcc options, rerun it and attach the resulting .i file) and exact gcc version you used).