This patch adds test gcc.dg/strncmp-2.c for builtin expansion of
strncmp and strcmp. This tests a couple more things such as differences
that occur after the zero byte, and something that glibc does which is
to call strncmp with SIZE_MAX for the length which looks for overflow
issues.

I've included interested parties from targets that have a strncmp
builtin.

The test passes on x86_64 and on ppc64le with -mcpu=power6. It will not
pass on ppc64/ppc64le -mcpu=power[78] until I check in my patch that
segher ack'd yesterday and is currently regtesting. OK for trunk?

-- 
Aaron Sawdey, Ph.D.  acsawdey@linux.vnet.ibm.com
050-2/C113  (507) 253-7520 home: 507/263-0782
IBM Linux Technology Center - PPC Toolchain