Don't force MALLOC_CHECK_ if already set
Don't force MALLOC_CHECK_ if already set

riusksk/riufuzz,riusksk/riufuzz,google/honggfuzz,riusksk/riufuzz,riusksk/riufuzz,anestisb/honggfuzz,riusksk/riufuzz,google/honggfuzz,riusksk/riufuzz,google/honggfuzz,riusksk/riufuzz