S390: Support -mtune=native and -march=native.

S390: Support -mtune=native and -march=native.

gcc/ChangeLog

2015-06-01  Dominik Vogt  <vogt@linux.vnet.ibm.com>

	    * config/s390/driver-native.c: New file.
	    * config/s390/x-native: New file.
	    * config.host: Add new files for s390.
	    * config/s390/s390.h (DRIVER_SELF_SPECS): Add support for -mtune=native
	    and -march=native
	    * config.gcc: Likewise.
	    * config/s390/s390.opt (march): Likewise; add PROCESSOR_NATIVE
	    * config/s390/s390-opts.h (enum processor_type): Ditto.
	    * config/s390/s390.c (s390_option_override): Catch unhandled
	    PROCESSOR_NATIVE

From-SVN: r223934