fixes issue 944 + check for overflow on malloc request size
fixes issue 944
+ check for overflow on malloc request size

SVN-Revision: 929

LohithBlaze/drmemory,code4bones/drmemory,code4bones/drmemory,sigma-random/drmemory,sigma-random/drmemory,LohithBlaze/drmemory,code4bones/drmemory,sigma-random/drmemory,code4bones/drmemory,code4bones/drmemory,LohithBlaze/drmemory,sigma-random/drmemory,sigma-random/drmemory,LohithBlaze/drmemory,LohithBlaze/drmemory