relibc: integrate upstream wchar.h include ordering + stdbool.h POSIX fix

Two upstream improvements integrated:

1. wchar.h cbindgen.toml — adopt upstream include ordering:
   - Remove redundant wchar_t redefinition (now provided by bits/wchar-t.h)
   - Define wint_t BEFORE #include <stddef.h> (conflict with GCC __need_wint_t)
   - Drop sys_includes, use no_includes=true (all includes in after_includes)
   - Cleaner circular-dependency breaking (wchar.h → stdio.h → inttypes.h → wchar.h)

2. stdbool.h — fix to POSIX standard:
   - Change 'typedef _Bool bool' to '#define bool _Bool' (C mode)
   - Remove 'typedef bool _Bool' (C++ mode, not in POSIX)
   - Only emit bool/true/false defines in C++ when __cplusplus < 201103L

include/stdbool.h

@@ -2,12 +2,12 @@
 #define _STDBOOL_H
 
 #ifndef __cplusplus
-typedef _Bool bool;
+#define bool _Bool
 #define true 1
 #define false 0
 #else /* __cplusplus */
-typedef bool _Bool;
 #if __cplusplus < 201103L
+#define bool bool
 #define false false
 #define true true
 #endif /*__cplusplus < 201103L*/

src/header/wchar/cbindgen.toml

@@ -1,17 +1,9 @@
-sys_includes = ["features.h", "stddef.h", "stdarg.h", "stdio.h"]
+# wint_t defined before stddef.h to avoid conflict with GCC's __need_wint_t.
+# wchar_t provided by bits/wchar-t.h → stddef.h (no local redefinition needed).
+# mbstate_t defined before transitive includes to break circular chains:
+#   wchar.h → stdio.h → inttypes.h → wchar.h (gnulib-based: m4, bison, flex).
 after_includes = """
-// int32_t, uint32_t, WCHAR_MIN, WCHAR_MAX
-#include <stdint.h>
-
-#ifndef _WCHAR_T
-#define _WCHAR_T
-#ifndef __cplusplus
-    #ifndef __WCHAR_TYPE__
-        #define __WCHAR_TYPE__ int32_t
-    #endif
-    typedef __WCHAR_TYPE__ wchar_t;
-#endif // __cplusplus
-#endif // _WCHAR_T
+#include <stdint.h> // for uint32_t, WCHAR_MIN, WCHAR_MAX
 
 #ifndef _WINT_T
 #define _WINT_T
@@ -21,32 +13,24 @@ after_includes = """
     typedef __WINT_TYPE__ wint_t;
 #endif // _WINT_T
 
-// Define mbstate_t before headers that may transitively re-include wchar.h.
-// The circular chain wchar.h → stdio.h → inttypes.h → wchar.h (and also
-// stdlib.h → wchar.h) would otherwise cause wint_t and mbstate_t to be
-// undefined in gnulib's wchar.h wrapper, breaking m4, bison, and other
-// gnulib-based packages.
 #ifndef _RELIBC_MBSTATE_T
 #define _RELIBC_MBSTATE_T
 typedef struct {} mbstate_t;
 #endif
 
-// Now include headers that depend on wchar_t/wint_t/mbstate_t.
-// These must come after the type definitions to break circular includes.
-#include <stdio.h>
-#include <time.h>
-
-// NULL, size_t, must come after wchar_t and wint_t
+// wchar_t comes from stddef.h → bits/wchar-t.h
 #define __need_size_t
 #define __need_NULL
 #include <stddef.h>
+#include <stdio.h>  // for FILE
+#include <time.h>   // for struct tm
 
 #define WEOF (0xffffffffu)
 """
 include_guard = "_RELIBC_WCHAR_H"
 language = "C"
 style = "Type"
-no_includes = false
+no_includes = true
 cpp_compat = true
 
 [export]