Disable tail call optimization and use -mstackrealign to boot up on fugu.

http://llvm.org/bugs/show_bug.cgi?id=15086,
llvm tail call optimization is wrong for x86.

For Android/x86 to use SSE* instructions safely, stack should be 16-byte
aligned before JNI function call, which isn't true for all x86 device,
so -mstackrealign should be the default.

BUG: 19234330
Change-Id: I4c6676366788772dbe64fd7f0dd33b3ed5c9b80e