Performing substitutions during post-patch breaks tools such as mkpatches,
making it very difficult to regenerate correct patches after making changes,
and often leading to substituted string replacements being committed.
(1) nios2-gcc 3.4.6 renamed to nios2-gcc3
(2) nios2-binutils 2.20 renamed to nios2-bintuils220
(3) nios2-gcc41 4.1.2 is imported from wip
nios2/Makefile.common, used be for (1) and (2) are
now for (2) and (3).