* testsuite/libgomp.oacc-c++/firstprivate-mappings-1.C: Add
	#define DO_LONG_DOUBLE; set to 1, except for nvidia + gcn.
	* libgomp.oacc-c-c++-common/firstprivate-mappings-1.c: Likewise.

	* g++.dg/goacc/firstprivate-mappings-1.C: Only set DO_LONG_DOUBLE if
	not defined; update comments.
	* c-c++-common/goacc/firstprivate-mappings-1.c: Likewise.