GCC47: Add local modifications

GCC47: Add local modifications

The majority of these changes are new files required to build GCC on
DragonFly.  They are identical to the lang/gcc-aux modifications.  Of
interest:

1) The modification to c-format.c is a carry-over from GCC44. It
   maintains support for the DragonFly-specific %b and %D conversions.
2) The modification to tree-inline.c is a carry-over from GCC44. It
   maintains the suppression of "unlikely call" inline warnings.
3) The gcc driver was modified to strip out all the bad paths in its
   search path.  gcc -print-search-dirs is now short and accurate.