tools/nolibc/ctype: split the is* functions to ctype.h

In fact there's only isdigit() for now. More should definitely be added.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/include/nolibc/ctype.h

+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * ctype function definitions for NOLIBC
+ * Copyright (C) 2017-2021 Willy Tarreau <w@1wt.eu>
+ */
+
+#ifndef _NOLIBC_CTYPE_H
+#define _NOLIBC_CTYPE_H
+
+#include "std.h"
+
+/*
+ * As much as possible, please keep functions alphabetically sorted.
+ */
+
+static __attribute__((unused))
+int isdigit(int c)
+{
+	return (unsigned int)(c - '0') <= 9;
+}
+
+#endif /* _NOLIBC_CTYPE_H */

tools/include/nolibc/nolibc.h

@@ -87,18 +87,13 @@
 #include "arch.h"
 #include "types.h"
 #include "sys.h"
+#include "ctype.h"
 #include "stdlib.h"
 #include "string.h"
 
 /* Used by programs to avoid std includes */
 #define NOLIBC
 
-static __attribute__((unused))
-int isdigit(int c)
-{
-	return (unsigned int)(c - '0') <= 9;
-}
-
 static __attribute__((unused))
 const char *ltoa(long in)
 {