Improve robustness of back_from_native_retstubs: On MacOS the XCode-installed assembler is the old nasm pre-1.0 and it won't generate the push or jmp encoding we want in back_from_native_retstubs, so this commit forces the small push via raw bytes and the short jump via the "short" keyword.
Improve robustness of back_from_native_retstubs:
On MacOS the XCode-installed assembler is the old nasm pre-1.0 and it won't
generate the push or jmp encoding we want in back_from_native_retstubs, so
this commit forces the small push via raw bytes and the short jump via the
"short" keyword.

SVN-Revision: 2978

AmesianX/dynamorio,sigma-random/dynamorio,daksunt/dynamorio,code4bones/dynamorio,AmesianX/dynamorio,daksunt/dynamorio,sigma-random/dynamorio,sigma-random/dynamorio,code4bones/dynamorio,code4bones/dynamorio,daksunt/dynamorio,AmesianX/dynamorio,bl4ckic3/dynamorio,daksunt/dynamorio,bl4ckic3/dynamorio,sigma-random/dynamorio,AmesianX/dynamorio,sigma-random/dynamorio,bl4ckic3/dynamorio,bl4ckic3/dynamorio,AmesianX/dynamorio,bl4ckic3/dynamorio,code4bones/dynamorio,code4bones/dynamorio,daksunt/dynamorio