If 'use'ing with an old GCC a new module file (with OpenACC 'routine'
directive's level of parallelism encoded), then that expectedly fails as
follows:

    f951: Fatal Error: Reading module 'routine_module_mod_1' at line 27 column 21: find_enum(): Enum not found

If 'use'ing with a new GCC an old module file (without OpenACC 'routine'
directive's level of parallelism encoded), then that (silently) continues to
accept the module file, and will proceed with the previous, erroneous behavior.

These seem to be acceptable compromises, instead of incrementing 'MOD_VERSION'.

	gcc/fortran/
	PR fortran/72741
	* module.c (verify_OACC_ROUTINE_LOP_NONE): New function.
	(enum ab_attribute): Add AB_OACC_ROUTINE_LOP_GANG,
	AB_OACC_ROUTINE_LOP_WORKER, AB_OACC_ROUTINE_LOP_VECTOR,
	AB_OACC_ROUTINE_LOP_SEQ.
	(attr_bits): Add these.
	(mio_symbol_attribute): Handle these.
	gcc/testsuite/
	PR fortran/72741
	* gfortran.dg/goacc/routine-module-1.f90: New file.
	* gfortran.dg/goacc/routine-module-2.f90: Likewise.
	* gfortran.dg/goacc/routine-module-mod-1.f90: Likewise.

From-SVN: r269855