c/c++, asm: Use nicer error for duplicate asm qualifiers

c/c++, asm: Use nicer error for duplicate asm qualifiers

Also as suggested by Jason.

c/
	* c-parser.c (c_parser_asm_statement): Keep track of the location each
	asm qualifier is first seen; use that to give nicer "duplicate asm
	qualifier" messages.  Delete 'quals" variable, instead pass the
	"is_volatile_ flag to build_asm_stmt directly.
	* c-tree.h (build_asm_stmt): Make the first arg bool instead of tree.
	* c-typeck.c (build_asm_stmt): Ditto; adjust.

cp/
	* parser.c (cp_parser_asm_definition): Rewrite the loop to work without
	"done" boolean variable.
	* parser.c (cp_parser_asm_definition): Keep track of the location each
	asm qualifier is first seen; use that to give nicer "duplicate asm
	qualifier" messages.

From-SVN: r267278