build system x86: deprecate bootblock_lds and ldscripts variables

Instead of keeping this separate variable around, add linker scripts
to the $(class)-y source lists and let the build system sort things out.

This is inspired by the commit listed below, but rewritten to match
upstream, and split in smaller pieces to keep intent clear.

Change-Id: I4af687becf2971e009cb077debc902d2f0722cfb
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Based-On-Change-Id: I50af7dacf616e0f8ff4c43f4acc679089ad7022b
Based-On-Signed-off-by: Julius Werner <jwerner@chromium.org>
Based-On-Reviewed-on: https://chromium-review.googlesource.com/219170
Reviewed-on: http://review.coreboot.org/9289
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>

Makefile.inc

@@ -113,8 +113,8 @@ files-in-dir=$(filter-out $(call dir-wildcards,$(call filter-out-dirs,$(1),$(sor
 # reduce command line length by linking the objects of each
 # directory into an intermediate file
 ramstage-postprocess=$(foreach d,$(sort $(dir $(1))), \
-	$(eval $(d)ramstage.o: $(call files-in-dir,$(d),$(1)); $$(LD_ramstage) -o $$@ -r $$^ ) \
-	$(eval ramstage-objs:=$(d)ramstage.o $(filter-out $(call files-in-dir,$(d),$(1)),$(ramstage-objs))))
+	$(eval $(d)ramstage.o: $(call files-in-dir,$(d),$(filter-out %.ld,$(1))); $$(LD_ramstage) -o $$@ -r $$^ ) \
+	$(eval ramstage-objs:=$(d)ramstage.o $(filter-out $(call files-in-dir,$(d),$(1)),$(filter-out %.ld,$(ramstage-objs)))))
 
 romstage-generic-ccopts += -D__PRE_RAM__
 ifeq ($(CONFIG_TRACE),y)
@@ -139,6 +139,15 @@ romstage-c-deps:=$$(OPTION_TABLE_H)
 verstage-c-deps:=$$(OPTION_TABLE_H)
 bootblock-c-deps:=$$(OPTION_TABLE_H)
 
+# Add handler to copy linker scripts
+define generic-objs_ld_template_gen
+de$(EMPTY)fine $(1)-objs_ld_template
+$$(call src-to-obj,$1,$$(1).ld): $$(1).ld
+	@printf "    CP         $$$$(subst $$$$(obj)/,,$$$$(@))\n"
+	cp $$$$< $$$$@
+en$(EMPTY)def
+endef
+
 # Add handler to add no rules for manual files
 define generic-objs_manual_template_gen
 # do nothing