diff --git a/libc/include/stdlib.h b/libc/include/stdlib.h
index d9d277a..88930b1 100644
--- a/libc/include/stdlib.h
+++ b/libc/include/stdlib.h
@@ -135,6 +135,8 @@
 int ptsname_r(int, char*, size_t);
 int unlockpt(int);
 
+int getsubopt(char**, char* const*, char**);
+
 typedef struct {
     int  quot;
     int  rem;