gcc: sandbox within series release number only

Fixes #33948.
Revision formulae that use gfortran for GCC bump
Revision formulae that are built against Homebrew libstdc++
fftw: update 3.3.4_1 bottle.
gcc: update 4.9.2_1 bottle.
grib-api: update 1.12.3_1 bottle.
gringo: update 4.4.0_1 bottle.
inkscape: update 0.48.5_1 bottle.
jags: add 3.4.0_1 bottle.
libgetdata: update 0.8.5_1 bottle.
libxc: update 2.2.0_1 bottle.
mpich2: update 3.1.3_1 bottle.
pgplot: add 5.2.2_1 bottle.
qd: add 2.3.14_1 bottle.
salt: add 2.4_1 bottle.