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_*.
Since essentially everything is linked to libmozglue and libmozglue takes
precedence in symbol resolution in our dynamic linker, there is no need
to wrap most symbols. PR_GetEnv/PR_SetEnv still needs wrapping because
there's no other way to actually wrap the calls from NSPR itself and NSS,
as well as the symbols wrapped because our dynamic linker can't find them
in system libraries on some devices because they're weak.