diff --git a/src/cmd/5l/asm.c b/src/cmd/5l/asm.c
index a26d5e209da..7ceea59b674 100644
--- a/src/cmd/5l/asm.c
+++ b/src/cmd/5l/asm.c
@@ -105,6 +105,12 @@ adddynrel(Sym *s, Reloc *r)
 	diag("adddynrel: unsupported binary format");
 }
 
+void
+adddynsym(Sym *s)
+{
+	diag("adddynsym: not implemented");
+}
+
 static void
 elfsetupplt(void)
 {