[Bug driver/63881] New: [5 Regression] patch to error out when input file is the same as output file causes glibc's config to fail

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63881

            Bug ID: 63881
           Summary: [5 Regression] patch to error out when input file is
                    the same as output file causes glibc's config to fail
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: driver
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org

glibc's log has this:
configure:95: checking for SSE4 support
configure:101:
/data1/src/gcc-cavium/toolchain-thunder/scripts/../minimal-i686-montavista-linux-gnu/bin/i686-montavista-linux-gnu-gcc
-m32 -O2 -msse4 -xc /dev/null -S -o /dev/null
i686-montavista-linux-gnu-gcc: fatal error: input file '/dev/null' is the same
as output file


Which is incorrect as /dev/null is a special file and should be handled
differently.