On PPC64, 'func' and 'main' are function descriptors and don't point
to the actual code. Thus the usage of these symbols in the DWARF
assembler source was broken. The patch introduces new labels
func_start and func_end for this purpose.
Two modifications:
1. The addition of 2013 to the copyright year range for every file;
2. The use of a single year range, instead of potentially multiple
year ranges, as approved by the FSF.
