--- a/lib/readline/Makefile.in
+++ b/lib/readline/Makefile.in
@@ -57,7 +57,7 @@ DEBUG = @DEBUG@
 ADDON_CFLAGS = 
 
 CFLAGS = @CFLAGS@
-LOCAL_CFLAGS = @LOCAL_CFLAGS@ ${DEBUG}
+LOCAL_CFLAGS = @LOCAL_CFLAGS@ ${DEBUG} -DNEED_EXTERN_PC
 STYLE_CFLAGS = @STYLE_CFLAGS@
 CPPFLAGS = @CPPFLAGS@
 LDFLAGS = @LDFLAGS@