build system: make CONFIG_* symbols disappear from objects

We don't actually want to see them in the binaries.

Change-Id: I37b53ef7dcbe05d81a8322d528c9aae102115134
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Reviewed-on: http://review.coreboot.org/9180
Tested-by: build bot (Jenkins)
Reviewed-by: Aaron Durbin <adurbin@google.com>
diff --git a/Makefile.inc b/Makefile.inc
index e80c2668..81b4c2b 100644
--- a/Makefile.inc
+++ b/Makefile.inc
@@ -246,7 +246,7 @@
 	mv $(obj)/build.ht $(obj)/build.h
 
 $(obj)/ldoptions: $(obj)/config.h
-	awk '/^#define ([^"])* ([^"])*$$/ {gsub("\\r","",$$3); print $$2 " = " $$3 ";";}' $< > $@
+	awk '/^#define ([^"])* ([^"])*$$/ {gsub("\\r","",$$3); print "PROVIDE_HIDDEN(" $$2 " = " $$3 ");";}' $< > $@
 
 build-dirs:
 	mkdir -p $(objcbfs) $(objgenerated)