--- client/frontier_config.c	2020-07-28 09:20:59.456311478 +0200
+++ client/frontier_config.c	2020-07-28 09:26:49.147996572 +0200
@@ -47,8 +47,8 @@
 
 #define ENV_BUF_SIZE	1024
 
-void *(*frontier_mem_alloc)(size_t size);
-void (*frontier_mem_free)(void *ptr);
+extern void *(*frontier_mem_alloc)(size_t size);
+extern void (*frontier_mem_free)(void *ptr);
 
 int frontier_pacparser_init(void);