pua_reginfo: Avoid clearing LIBS= flags during build

This breaks CI by clearing "-flto", which leads to unrecognizable ".o"
files which the linker assumes to be bytecode (hint, hint: they are not).

Thanks to Răzvan Crainea for helping troubleshoot this!

modules/pua_reginfo/Makefile

@@ -6,7 +6,6 @@
 include ../../Makefile.defs
 auto_gen=
 NAME=pua_reginfo.so
-LIBS=
 
 ifeq ($(CROSS_COMPILE),)
 XML2CFG=$(shell which xml2-config)
@@ -22,8 +21,8 @@ ifneq ($(XML2CFG),)
 	DEFS += $(shell $(XML2CFG) --cflags )
 	LIBS += $(shell $(XML2CFG) --libs)
 else
-	DEFS+=-I$(LOCALBASE)/include/libxml2 -I$(LOCALBASE)/include
-	LIBS+=-L$(LOCALBASE)/lib -lxml2
+	DEFS += -I$(LOCALBASE)/include/libxml2 -I$(LOCALBASE)/include
+	LIBS += -L$(LOCALBASE)/lib -lxml2
 endif
 
 include ../../Makefile.modules