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 modificati

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.

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