stack-protector configure test and MIPS64

[Roland McGrath]

> The following patch does that.  It suffices to make the build work for 
> MIPS64; also tested with a full build and testsuite run for x86_64.

My paranoia would be happier with a check that doesn't get confused by
a version of -fstack-protector that emits some symbol other than
__stack_chk_fail.  In fact, it looks like my check would be confused
by an i386 or powerpc GCC that set -fPIC by default (because then it
would call __stack_chk_fail_local).  Such confusion today is a hard
error.  Your change would turn that error into a false negative, which
troubles me.


Thanks,
Roland