Add support for __builtin_init_heap_trampoline, fixing PR16015.  While there,
implement -Wtrampolines.


git-svn-id: https://llvm.org/svn/llvm-project/dragonegg/trunk@182705 91177308-0d34-0410-b5e6-96231b3b80d8
Force SSE on so that the vectorizer will do something on 32 bit platforms.
This will hopefully fix the 32 bit dragonegg buildbots.


git-svn-id: https://llvm.org/svn/llvm-project/dragonegg/trunk@182707 91177308-0d34-0410-b5e6-96231b3b80d8