PR ld/12356

	PR ld/12356
	* ldexp.h (exp_assop): Delete.
	(exp_assign, exp_defsym): Declare.
	* ldexp.c (exp_assop): Make static, handle all assignment variations.
	(exp_assign, exp_defsym): New functions.
	(exp_provide): Use exp_assop.
	* ldgram.y (defsym_expr): Use exp_defsym.
	* ldctor.c, * ldgram.y, * ldlang.c, * mri.c, * emultempl/beos.em,
	* emultempl/pe.em, * emultempl/pep.em, * emultempl/spuelf.em,
	* emultempl/xtensaelf.em: Update exp_assop -> exp_assign.