re PR fortran/71704 (ICE with -fopenmp and some omp constructs)

re PR fortran/71704 (ICE with -fopenmp and some omp constructs)

	PR fortran/71704
	* parse.c (matchs, matcho): Move right before decode_omp_directive.
	If spec_only, only gfc_match the keyword and if successful, goto
	do_spec_only.
	(matchds, matchdo): Define.
	(decode_omp_directive): Add spec_only local var and set it.
	Use matchds or matchdo macros instead of matchs or matcho
	for declare target, declare simd, declare reduction and threadprivate
	directives.  Return ST_GET_FCN_CHARACTERISTICS if a non-declarative
	directive could be matched.
	(next_statement): For ST_GET_FCN_CHARACTERISTICS restore
	gfc_current_locus from old_locus even if there is no label.

	* gfortran.dg/gomp/pr71704.f90: New test.

From-SVN: r237888