tools/nolibc/std: move the standard type definitions to std.h

The ordering of includes and definitions for now is a bit of a mess, as
for example asm/signal.h is included after int definitions, but plenty of
structures are defined later as they rely on other includes.

Let's move the standard type definitions to a dedicated file that is
included first. We also move NULL there. This way all other includes
are aware of it, and we can bring asm/signal.h back to the top of the
file.
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

tools/include/nolibc/nolibc.h

@@ -83,7 +83,12 @@
 #ifndef _NOLIBC_H
 #define _NOLIBC_H
 
+/* standard type definitions */
+#include "std.h"
+
+/* system includes */
 #include <asm/unistd.h>
+#include <asm/signal.h>  // for SIGCHLD
 #include <asm/ioctls.h>
 #include <asm/errno.h>
 #include <linux/fs.h>
@@ -106,40 +111,6 @@ static int errno;
  */
 #define MAX_ERRNO 4095
 
-/* Declare a few quite common macros and types that usually are in stdlib.h,
- * stdint.h, ctype.h, unistd.h and a few other common locations.
- */
-
-#define NULL ((void *)0)
-
-/* stdint types */
-typedef unsigned char       uint8_t;
-typedef   signed char        int8_t;
-typedef unsigned short     uint16_t;
-typedef   signed short      int16_t;
-typedef unsigned int       uint32_t;
-typedef   signed int        int32_t;
-typedef unsigned long long uint64_t;
-typedef   signed long long  int64_t;
-typedef unsigned long        size_t;
-typedef   signed long       ssize_t;
-typedef unsigned long     uintptr_t;
-typedef   signed long      intptr_t;
-typedef   signed long     ptrdiff_t;
-
-/* for stat() */
-typedef unsigned int          dev_t;
-typedef unsigned long         ino_t;
-typedef unsigned int         mode_t;
-typedef   signed int          pid_t;
-typedef unsigned int          uid_t;
-typedef unsigned int          gid_t;
-typedef unsigned long       nlink_t;
-typedef   signed long         off_t;
-typedef   signed long     blksize_t;
-typedef   signed long      blkcnt_t;
-typedef   signed long        time_t;
-
 /* for poll() */
 struct pollfd {
 	int fd;
@@ -248,9 +219,6 @@ struct stat {
 #define WEXITSTATUS(status)   (((status) & 0xff00) >> 8)
 #define WIFEXITED(status)     (((status) & 0x7f) == 0)
 
-/* for SIGCHLD */
-#include <asm/signal.h>
-
 /* Below comes the architecture-specific code. For each architecture, we have
  * the syscall declarations and the _start code definition. This is the only
  * global part. On all architectures the kernel puts everything in the stack

tools/include/nolibc/std.h

+/* SPDX-License-Identifier: LGPL-2.1 OR MIT */
+/*
+ * Standard definitions and types for NOLIBC
+ * Copyright (C) 2017-2021 Willy Tarreau <w@1wt.eu>
+ */
+
+#ifndef _NOLIBC_STD_H
+#define _NOLIBC_STD_H
+
+/* Declare a few quite common macros and types that usually are in stdlib.h,
+ * stdint.h, ctype.h, unistd.h and a few other common locations. Please place
+ * integer type definitions and generic macros here, but avoid OS-specific and
+ * syscall-specific stuff, as this file is expected to be included very early.
+ */
+
+/* note: may already be defined */
+#ifndef NULL
+#define NULL ((void *)0)
+#endif
+
+/* stdint types */
+typedef unsigned char       uint8_t;
+typedef   signed char        int8_t;
+typedef unsigned short     uint16_t;
+typedef   signed short      int16_t;
+typedef unsigned int       uint32_t;
+typedef   signed int        int32_t;
+typedef unsigned long long uint64_t;
+typedef   signed long long  int64_t;
+typedef unsigned long        size_t;
+typedef   signed long       ssize_t;
+typedef unsigned long     uintptr_t;
+typedef   signed long      intptr_t;
+typedef   signed long     ptrdiff_t;
+
+/* those are commonly provided by sys/types.h */
+typedef unsigned int          dev_t;
+typedef unsigned long         ino_t;
+typedef unsigned int         mode_t;
+typedef   signed int          pid_t;
+typedef unsigned int          uid_t;
+typedef unsigned int          gid_t;
+typedef unsigned long       nlink_t;
+typedef   signed long         off_t;
+typedef   signed long     blksize_t;
+typedef   signed long      blkcnt_t;
+typedef   signed long        time_t;
+
+#endif /* _NOLIBC_STD_H */