lib/Makefile: Add ability to specify -ldflags for rmodules

This will allow linker flag customization for rmodules.

BUG=b:221231786
TEST=Build guybrush with patch train and verify ldflags are passed

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Change-Id: Ib65476759e79c49d90856dcd7ee76d7d6e8a679a
Reviewed-on: https://review.coreboot.org/c/coreboot/+/62400
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Martin Roth <martinroth@google.com>
diff --git a/src/lib/Makefile.inc b/src/lib/Makefile.inc
index 8d235a9..5e3ce50 100644
--- a/src/lib/Makefile.inc
+++ b/src/lib/Makefile.inc
@@ -318,7 +318,7 @@
 # rmdoule is named $(1).rmod
 define rmodule_link
 $(strip $(1)): $(strip $(2)) $$(COMPILER_RT_rmodules_$(4)) $(call src-to-obj,rmodules_$(4),src/lib/rmodule.ld) | $$(RMODTOOL)
-	$$(LD_rmodules_$(4)) $$(LDFLAGS_rmodules_$(4)) $(RMODULE_LDFLAGS) -T $(call src-to-obj,rmodules_$(4),src/lib/rmodule.ld) --defsym=__heap_size=$(strip $(3)) -o $$@ --whole-archive --start-group $(filter-out %.ld,$(2)) --end-group
+	$$(LD_rmodules_$(4)) $$(LDFLAGS_rmodules_$(4)) $(RMODULE_LDFLAGS) $($(1)-ldflags) -T $(call src-to-obj,rmodules_$(4),src/lib/rmodule.ld) --defsym=__heap_size=$(strip $(3)) -o $$@ --whole-archive --start-group $(filter-out %.ld,$(2)) --end-group
 	$$(NM_rmodules_$(4)) -n $$@ > $$(basename $$@).map
 endef