Pipe stderr to /dev/null when getting LIBCLANG_RT_FILE_NAME

Fix a warning when using gcc:
i386-elf-gcc: error: unrecognized command line option
'-print-librt-file-name'

Change-Id: I421933ede9ddbddad37544a62e428c79e9ee2c8d
Signed-off-by: Martin Roth <martin.roth@se-eng.com>
Reviewed-on: http://review.coreboot.org/7249
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Tested-by: build bot (Jenkins)
Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>
1 file changed