__ANDROID__ is a built-in compiler macro, but __BIONIC__ is defined by
the libc header.
Reviewed By: #libc_abi, compnerd
Differential Revision: https://reviews.llvm.org/D137128
When the sigreturn trampoline is found the unw_proc_info_t.end_ip need to be set to
indicate a stack frame is found.
Reviewed By: cjdb, #libunwind, MaskRay
Differential Revision: https://reviews.llvm.org/D124522