Bug 1094565 - Update sccache to e68dfc2. r=mshal
Bug 1094566 - Do not overwrite buildid on the compilation phase of PGO builds. r=mshal
Bug 1104173 - Properly export jemalloc_* symbols from the jemalloc3 replace-malloc library. r=njn

Bug 818922 made MOZ_REPLACE_MALLOC a global define, and that changed the
defines set when building mozjemalloc_compat.c for the jemalloc3
replace-malloc library. In turn, this made the symbol munging wrong for
that library, making the jemalloc_* functions exported as je_jemalloc_*
instead of replace_jemalloc_*.