ARM setjmp and r12

[Shaun Jackman]

On the ARM, why does setjmp preserve r12 (ip)?  I believe r12 is
caller-preserved, not callee-preserved.

arm/setjmp.S:122
	/* Save all the callee-preserved registers into the jump buffer.  */
	stmea		a1!, { v1-v7, fp, ip, sp, lr }

Cheers,
Shaun