diff --git a/src/common.h b/src/common.h
index e360145..a8a19ad 100644
--- a/src/common.h
+++ b/src/common.h
@@ -144,8 +144,6 @@ void read_password(char*, size_t);
 
 int check_topdomain(char *, char **);
 
-extern double difftime(time_t, time_t);
-
 #if defined(WINDOWS32) || defined(ANDROID)
 #ifndef ANDROID
 int inet_aton(const char *cp, struct in_addr *inp);