Disable Clang arm integrated assembler.

When src/cxa_exception.cpp is compiled with Clang assembler
__cxa_end_cleanup_impl, although marked as used, was discarded
since it is used only in embedded assembly code.
This caused the following warning when linking libc++.so:
libc++_static.a(cxa_exception.o)(.text.__cxa_end_cleanup+0x2):
warning: relocation refers to discarded section
See also http://llvm.org/bugs/show_bug.cgi?id=21292.

BUG: 17903051
Change-Id: Idfb56d9c65307231028f4e28313b06516f7d8b23
1 file changed