base: Revise Git exclusions
base: Revise Git exclusions

- The build no longer produces *.dSYM directories.

- Re-anchor exclusions that I accidentally unmoored.

- Restrain broad exclusions to specific points in the directory tree.

- Replace exclusions of several individual files with more general
  exclude/include pairs.

git-svn-id: 620571fa9b4bd0cbce9a0cf901e91ef896adbf27@151568 d073be05-634f-4543-b044-5fe20cf6d1d6

macports/macports-base,danchr/macports-base,neverpanic/macports-base,neverpanic/macports-base,danchr/macports-base,macports/macports-base