S/390: Rename __S390_ARCH_LEVEL__ to __ARCH__.

S/390: Rename __S390_ARCH_LEVEL__ to __ARCH__.

We have recently added the predefined macro __S390_ARCH_LEVEL__ to
expand to a numerical value representing the architecture document
level currently in use.  However, the IBM XL compiler already has a
macro named __ARCH__ for that purpose.  So we change our macro to that
in order to improve portability.

gcc/ChangeLog:

2017-01-31  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* config/s390/s390-c.c (s390_cpu_cpp_builtins_internal): Rename
	__S390_ARCH_LEVEL__ to __ARCH__.

gcc/testsuite/ChangeLog:

2017-01-31  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* gcc.target/s390/s390.exp: Rename __S390_ARCH_LEVEL__ to
	__ARCH__.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@245055 138bc75d-0d04-0410-961f-82ee72b054a4