use new a_crash() asm to optimize double-free handler.
[musl] / src / setjmp /
drwxr-xr-x   ..
drwxr-xr-x - i386
-rw-r--r-- 0 longjmp.c
-rw-r--r-- 0 setjmp.c
drwxr-xr-x - x86_64