tools/nolibc/time: create time.h with time()

The time() syscall is used by a few simple applications, and is trivial
to implement based on gettimeofday() that we already have. Let's create
the file to ease porting and provide the function. It never returns any
error, though it may segfault in case of invalid pointer, like other
implementations relying on gettimeofday().
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/include/nolibc/nolibc.h

@@ -92,6 +92,7 @@
 #include "stdio.h"
 #include "stdlib.h"
 #include "string.h"
+#include "time.h"
 #include "unistd.h"
 
 /* Used by programs to avoid std includes */

tools/include/nolibc/time.h

+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * time function definitions for NOLIBC
+ * Copyright (C) 2017-2022 Willy Tarreau <w@1wt.eu>
+ */
+
+#ifndef _NOLIBC_TIME_H
+#define _NOLIBC_TIME_H
+
+#include "std.h"
+#include "arch.h"
+#include "types.h"
+#include "sys.h"
+
+static __attribute__((unused))
+time_t time(time_t *tptr)
+{
+	struct timeval tv;
+
+	/* note, cannot fail here */
+	sys_gettimeofday(&tv, NULL);
+
+	if (tptr)
+		*tptr = tv.tv_sec;
+	return tv.tv_sec;
+}
+
+#endif /* _NOLIBC_TIME_H */