gcc: fix system argument separation.
gcc: don't configure with version suffix.

Just add symlinks for gcc, g++ for backwards compatibility.

Closes #29309.
gcc: build gfortran by default.
fortran_dependency: use gcc instead of gfortran.
Remove gfortran in favour of gcc formula.
gcc: bump revision for version suffix changes.
gcc: update 4.8.2_1 bottle.

Closes #28855.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
git-annex: use unversioned gcc binary name.
git-annex: update 5.20140421 bottle.