* libc/machine/arm/setjmp.S: Add Thumb-2 support. * libc/sys/arm/crt0.S: Add Thumb-2 startup code. * libc/sys/arm/libcfunc.c (do_AngelSWI): Use AngelSWIInsn. * libc/sys/arm/swi.h (AngelSWIInsn, AngelSWIAsm): Define. * libc/sys/arm/trap.S: Disable for Thumb-2.