fix $-escaping in mk/package.mk

Obviously a typo, since the line above the variable fn is referenced
using '$$$$fn'. Escaping in templates is infernal. ;)

mk/package.mk

@@ -233,7 +233,7 @@ endif
 	@cd '$${STAGING_DIR}'; grep 'usr/lib/.*\.la$$$$' \
 	    '$${STAGING_PARENT}/pkg/$(1)' | while read fn; do \
 		chmod u+w $$$$fn; \
-		$(SED) "s,\(^libdir='\| \|-L\|^dependency_libs='\)/usr/lib,\1$(STAGING_DIR)/usr/lib,g" $$fn; \
+		$(SED) "s,\(^libdir='\| \|-L\|^dependency_libs='\)/usr/lib,\1$(STAGING_DIR)/usr/lib,g" $$$$fn; \
 	done
 ifeq (,$(filter noscripts,$(7)))
 	@cd '$${STAGING_DIR}'; grep 'usr/s*bin/' \