Unreviewed patch (was: another bootstrap failure onsparc-sun-solaris28 in cp/xref.o)

[Richard Kenner]

    > However unaligned_integer_asm_op doesn't which makes
    > UNALIGNED_DOUBLE_INT_ASM_OP being null dangerous.
    
    I don't see the difference between abort and SEGV, myself.

Not all machines SEGV for null dereference, so testing for it is safer.