Support -B argument for GCC
Support -B argument for GCC

Fixes #126

mozilla/sccache,glandium/sccache,mozilla/sccache,luser/sccache2,glandium/sccache,luser/sccache2,luser/sccache2,luser/sccache2,glandium/sccache,mozilla/sccache,glandium/sccache