s390: Deprecate ESA/390 support

s390: Deprecate ESA/390 support

Deprecate support for the ESA/390 architecture which will be eventually
removed, and encourage the usage of the z/Architecture instead.

Furthermore, default for -m31 to -mzarch whereas previously we defaulted
to -mesa.

gcc/ChangeLog:

	* config.gcc: Fail in case of option --with-mode=esa.
	* config/s390/s390.cc (s390_option_override_internal): Default
	to z/Architecture mode.
	* config/s390/s390.h (DRIVER_SELF_SPECS): Ditto.
	* config/s390/s390.opt: Emit a warning for option -mesa.
	* doc/invoke.texi: Document the change.

gcc/testsuite/ChangeLog:

	* gcc.target/s390/20020926-1.c: Deal with deprecation warning.
	* gcc.target/s390/dwarfregtable-1.c: Ditto.
	* gcc.target/s390/fp2int1.c: Ditto.
	* gcc.target/s390/pr102222.c: Ditto.
	* gcc.target/s390/pr106355-3.c: Ditto.
	* gcc.target/s390/pr61078.c: Ditto.
	* gcc.target/s390/target-attribute/tattr-m31-10.c: Ditto.
	* gcc.target/s390/target-attribute/tattr-m31-12.c: Ditto.
	* gcc.target/s390/target-attribute/tattr-m31-14.c: Ditto.
	* gcc.target/s390/target-attribute/tattr-m31-18.c: Ditto.
	* gcc.target/s390/target-attribute/tattr-m31-2.c: Ditto.
	* gcc.target/s390/target-attribute/tattr-m31-20.c: Ditto.
	* gcc.target/s390/target-attribute/tattr-m31-22.c: Ditto.
	* gcc.target/s390/target-attribute/tattr-m31-24.c: Ditto.
	* gcc.target/s390/target-attribute/tattr-m31-26.c: Ditto.
	* gcc.target/s390/target-attribute/tattr-m31-28.c: Ditto.
	* gcc.target/s390/target-attribute/tattr-m31-30.c: Ditto.
	* gcc.target/s390/target-attribute/tattr-m31-32.c: Ditto.
	* gcc.target/s390/target-attribute/tattr-m31-4.c: Ditto.
	* gcc.target/s390/target-attribute/tattr-m31-6.c: Ditto.
	* gcc.target/s390/target-attribute/tattr-m31-8.c: Ditto.