tools/nolibc: add stdbool.h header

stdbool.h is very simple.
Provide an implementation for the user convenience.

Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/r/20240725-nolibc-stdbool-v1-1-a6ee2c80bcde@weissschuh.net
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>

tools/include/nolibc/Makefile

@@ -35,6 +35,7 @@ all_files := \
 		stackprotector.h \
 		std.h \
 		stdarg.h \
+		stdbool.h \
 		stdint.h \
 		stdlib.h \
 		string.h \

tools/include/nolibc/nolibc.h

@@ -74,7 +74,8 @@
  *            -I../nolibc -o hello hello.c -lgcc
  *
  * The available standard (but limited) include files are:
- *   ctype.h, errno.h, signal.h, stdarg.h, stdio.h, stdlib.h, string.h, time.h
+ *   ctype.h, errno.h, signal.h, stdarg.h, stdbool.h stdio.h, stdlib.h,
+ *   string.h, time.h
  *
  * In addition, the following ones are expected to be provided by the compiler:
  *   float.h, stddef.h

tools/include/nolibc/stdbool.h

@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * Boolean types support for NOLIBC
+ * Copyright (C) 2024 Thomas Weißschuh <linux@weissschuh.net>
+ */
+
+#ifndef _NOLIBC_STDBOOL_H
+#define _NOLIBC_STDBOOL_H
+
+#define bool _Bool
+#define true 1
+#define false 0
+
+#define __bool_true_false_are_defined 1
+
+#endif /* _NOLIBC_STDBOOL_H */