Add unlockpt(3).

libc/Makefile

@@ -541,6 +541,7 @@ stdlib/rand.o \
 stdlib/realpath.o \
 stdlib/setenv.o \
 stdlib/system.o \
+stdlib/unlockpt.o \
 stdlib/unsetenv.o \
 sys/display/dispmsg_issue.o \
 sys/ioctl/ioctl.o \

libc/include/stdlib.h

@@ -166,11 +166,11 @@ void setkey(const char*);
 char* setstate(char*);
 void srand48(long);
 void srandom(unsigned);
-int unlockpt(int);
 #endif
 
 #if __USE_SORTIX || __USE_XOPEN
 int grantpt(int);
+int unlockpt(int);
 #endif
 
 #if __USE_SORTIX || 600 <= __USE_XOPEN

libc/stdlib/unlockpt.c

@@ -0,0 +1,26 @@
+/*
+ * Copyright (c) 2016 Jonas 'Sortie' Termansen.
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * stdlib/unlockpt.c
+ * Unlock the pseudoterminal slave.
+ */
+
+#include <stdlib.h>
+
+int unlockpt(int fd)
+{
+	(void) fd;
+	return 0;
+}