openmp, fortran: Add Fortran support for indirect clause on the declare target directive

2024-02-15  Kwok Cheung Yeung  <kcyeung@baylibre.com>

	gcc/fortran/
	* dump-parse-tree.cc (show_attr): Handle omp_declare_target_indirect
	attribute.
	* f95-lang.cc (gfc_gnu_attributes): Add entry for 'omp declare
	target indirect'.
	* gfortran.h (symbol_attribute): Add omp_declare_target_indirect
	field.
	(struct gfc_omp_clauses): Add indirect field.
	* openmp.cc (omp_mask2): Add OMP_CLAUSE_INDIRECT.
	(gfc_match_omp_clauses): Match indirect clause.
	(OMP_DECLARE_TARGET_CLAUSES): Add OMP_CLAUSE_INDIRECT.
	(gfc_match_omp_declare_target): Check omp_device_type and apply
	omp_declare_target_indirect attribute to symbol if indirect clause
	active.  Show warning if there are only device_type and/or indirect
	clauses on the directive.
	* trans-decl.cc (add_attributes_to_decl): Add 'omp declare target
	indirect' attribute if symbol has indirect attribute set.

	gcc/testsuite/
	* gfortran.dg/gomp/declare-target-4.f90 (f1): Update expected warning.
	* gfortran.dg/gomp/declare-target-indirect-1.f90: New.
	* gfortran.dg/gomp/declare-target-indirect-2.f90: New.

	libgomp/
	* testsuite/libgomp.fortran/declare-target-indirect-1.f90: New.
	* testsuite/libgomp.fortran/declare-target-indirect-2.f90: New.
	* testsuite/libgomp.fortran/declare-target-indirect-3.f90: New.