* ld.h (parsing_defsym): Declare.

	* ld.h (parsing_defsym): Declare.
	* ldlex.h (lex_string): Declare.
	* ldlex.l (lex_string): Define.
	* lexsup.c (parsing_defsym): Define.
	(parse_args): In OPTION_DEFSYM case, set lex_string before calling
	lex_redirect, and clear it after calling yyparse.  Set
	parsing_defsym around call to yyparse.
	* ldmain.c (main): Set lex_string before calling lex_redirect, and
	clear it after calling yyparse.
	* ldmisc.c (vfinfo): For %S, handle --defsym arguments and built
	in linker scripts correctly.
PR 8092.