options/posix: Add missing declaration of ptsname in stdlib.h
@@ -33,6 +33,7 @@ char *realpath(const char *__restrict, char *__restrict);
int posix_openpt(int flags);
int grantpt(int fd);
int unlockpt(int fd);
+char *ptsname(int fd);
int ptsname_r(int fd, char *buf, size_t len);
#ifdef __cplusplus
