re PR fortran/13912 (Does not accept consecutive arithmetic operators (*-))

	PR fortran/13912
	* matchexp.c: Allow unary operators after arithmetic operators
	as a GNU extension.
	(match_ext_mult_operand, match_ext_add_operand): New functions.
	(match_mult_operand): Tweak to call match_ext_mult_operand.
	(match_add_operand): Tweak to call match_ext_mult_operand.
	(match_level_2): Rearrange to call match_ext_add_operand.

From-SVN: r82277