Fortran: Add 'device_type' clause to OpenMP's declare target

Fortran: Add 'device_type' clause to OpenMP's declare target

gcc/fortran/ChangeLog:

	* gfortran.h (enum gfc_omp_device_type): New.
	(symbol_attribute, gfc_omp_clauses, gfc_common_head): Use it.
	* module.c (enum ab_attribute): Add AB_OMP_DEVICE_TYPE_HOST,
	AB_OMP_DEVICE_TYPE_NOHOST and AB_OMP_DEVICE_TYPE_ANY.
	(attr_bits, mio_symbol_attribute): Handle it.
	(load_commons, write_common_0): Handle omp_device_type flag.
	* openmp.c (enum omp_mask1): Add OMP_CLAUSE_DEVICE_TYPE
	(OMP_DECLARE_TARGET_CLAUSES): Likewise.
	(gfc_match_omp_clauses): Match 'device_type'.
	(gfc_match_omp_declare_target): Handle it.
	* trans-common.c (build_common_decl): Write device-type clause.
	* trans-decl.c (add_attributes_to_decl): Likewise.

gcc/testsuite/ChangeLog:

	* gfortran.dg/gomp/declare-target-4.f90: New test.
	* gfortran.dg/gomp/declare-target-5.f90: New test.