* mkconfig.sh (DEFINES): Handle entries with '='.

	* config.gcc: Don't use i370/xm-mvs.h or ns32k/xm-pc532-min.h.
	Set xm_defines to MACRO=value instead.

	* i370/xm-mvs.h: Delete.

	* ns32k/xm-pc532-min.h: Likewise.

From-SVN: r40828