diff --git a/ungeli.c b/ungeli.c
index 3b41788..64b7d63 100644
--- a/ungeli.c
+++ b/ungeli.c
@@ -87,11 +87,15 @@ set_mkey(const char *arg) {
     hextobin(mkey, sizeof(mkey), arg);
 }
 
+static void
+perror_fatal(const char *s) __attribute__((noreturn));
 static void
 perror_fatal(const char *s) {
     perror(s); abort();
 }
 
+static void
+fatal(const char *s) __attribute__((noreturn));
 static void
 fatal(const char *s) {
     fprintf(stderr, "%s\n", s); abort();