Overall changes for C++

cfloat

@@ -0,0 +1,16 @@
+#ifndef __cplusplus
+#error "Must only use this header with C++"
+#endif
+
+#ifndef _CFLOAT
+#define _CFLOAT 1
+
+namespace std {
+
+#define __LIBC_GUARDLESS_INCLUDE
+#include <float.h>
+#undef __LIBC_GUARDLESS_INCLUDE
+
+}
+
+#endif

climits

@@ -0,0 +1,16 @@
+#ifndef __cplusplus
+#error "Must only use this header with C++"
+#endif
+
+#ifndef _CLIMITS
+#define _CLIMITS 1
+
+namespace std {
+
+#define __LIBC_GUARDLESS_INCLUDE
+#include <limits.h>
+#undef __LIBC_GUARDLESS_INCLUDE
+
+}
+
+#endif

cstdalign

@@ -0,0 +1,16 @@
+#ifndef __cplusplus
+#error "Must only use this header with C++"
+#endif
+
+#ifndef _CSTDALIGN
+#define _CSTDALIGN 1
+
+namespace std {
+
+#define __LIBC_GUARDLESS_INCLUDE
+#include <stdalign.h>
+#undef __LIBC_GUARDLESS_INCLUDE
+
+}
+
+#endif

cstdarg

@@ -0,0 +1,16 @@
+#ifndef __cplusplus
+#error "Must only use this header with C++"
+#endif
+
+#ifndef _CSTDARG
+#define _CSTDARG 1
+
+namespace std {
+
+#define __LIBC_GUARDLESS_INCLUDE
+#include <stdarg.h>
+#undef __LIBC_GUARDLESS_INCLUDE
+
+}
+
+#endif

cstdbool

@@ -0,0 +1,16 @@
+#ifndef __cplusplus
+#error "Must only use this header with C++"
+#endif
+
+#ifndef _CSTDBOOL
+#define _CSTDBOOL 1
+
+namespace std {
+
+#define __LIBC_GUARDLESS_INCLUDE
+#include <stdbool.h>
+#undef __LIBC_GUARDLESS_INCLUDE
+
+}
+
+#endif

cstddef

@@ -0,0 +1,16 @@
+#ifndef __cplusplus
+#error "Must only use this header with C++"
+#endif
+
+#ifndef _CSTDDEF
+#define _CSTDDEF 1
+
+namespace std {
+
+#define __LIBC_GUARDLESS_INCLUDE
+#include <stddef.h>
+#undef __LIBC_GUARDLESS_INCLUDE
+
+}
+
+#endif

cstdint

@@ -0,0 +1,16 @@
+#ifndef __cplusplus
+#error "Must only use this header with C++"
+#endif
+
+#ifndef _CSTDINT
+#define _CSTDINT 1
+
+namespace std {
+
+#define __LIBC_GUARDLESS_INCLUDE
+#include <stdint.h>
+#undef __LIBC_GUARDLESS_INCLUDE
+
+}
+
+#endif

float.h

@@ -1,5 +1,6 @@
+#if !defined(_FLOAT_H) || defined(__LIBC_GUARDLESS_INCLUDE)
+
 #ifndef _FLOAT_H
-#define _FLOAT_H 1
 
 #define FLT_ROUNDS 1
 
@@ -11,6 +12,10 @@
 
 #define DECIMAL_DIG __DECIMAL_DIG__
 
+#define FLT_DECIMAL_DIG __FLT_DECIMAL_DIG__
+#define DBL_DECIMAL_DIG __DBL_DECIMAL_DIG__
+#define LDBL_DECIMAL_DIG __LDBL_DECIMAL_DIG__
+
 #define FLT_EVAL_METHOD __FLT_EVAL_METHOD__
 
 #define FLT_DIG __FLT_DIG__
@@ -46,3 +51,9 @@
 #define LDBL_MIN __LDBL_MIN__
 
 #endif
+
+#if !defined(__LIBC_GUARDLESS_INCLUDE)
+#define _FLOAT_H 1
+#endif
+
+#endif

limits.h

@@ -1,5 +1,6 @@
+#if !defined(_LIMITS_H) || defined(__LIBC_GUARDLESS_INCLUDE)
+
 #ifndef _LIMITS_H
-#define _LIMITS_H 1
 
 #ifndef __LIBC_C_JOIN
 #   define __LIBC_C_EXPAND_JOIN(x, suffix) x ## suffix
@@ -8,6 +9,8 @@
 
 #define CHAR_BIT __CHAR_BIT__
 
+#define MB_LEN_MAX 16
+
 #define SCHAR_MAX __SCHAR_MAX__
 #define SCHAR_MIN (-SCHAR_MAX - 1)
 
@@ -42,3 +45,9 @@
 #define ULLONG_MAX (__LIBC_C_JOIN(LLONG_MAX, U) * 2 + 1)
 
 #endif
+
+#if !defined(__LIBC_GUARDLESS_INCLUDE)
+#define _LIMITS_H 1
+#endif
+
+#endif

stdalign.h

@@ -1,10 +1,20 @@
-#ifndef _STDALIGN_H
-#define _STDALIGN_H 1
+#if !defined(_STDALIGN_H) || defined(__LIBC_GUARDLESS_INCLUDE)
 
-#define alignas _Alignas
-#define alignof _Alignof
+#ifndef _STDALIGN_H
+
+#ifndef __cplusplus
+#  define alignas _Alignas
+#  define alignof _Alignof
+
+#  define __alignof_is_defined 1
+#endif
 
 #define __alignas_is_defined 1
-#define __alignof_is_defined 1
+
+#endif
+
+#if !defined(__LIBC_GUARDLESS_INCLUDE)
+#define _STDALIGN_H 1
+#endif
 
 #endif

stdarg.h

@@ -1,11 +1,18 @@
-#ifndef _STDARG_H
-#define _STDARG_H 1
+#if !defined(_STDARG_H) || defined(__LIBC_GUARDLESS_INCLUDE)
 
 typedef __builtin_va_list va_list;
 
+#ifndef _STDARG_H
+
 #define va_start(v, l) __builtin_va_start(v, l)
 #define va_end(v) __builtin_va_end(v)
 #define va_arg(v, l) __builtin_va_arg(v, l)
 #define va_copy(d, s) __builtin_va_copy(d, s)
 
 #endif
+
+#if !defined(__LIBC_GUARDLESS_INCLUDE)
+#define _STDARG_H 1
+#endif
+
+#endif

stdbool.h

@@ -1,11 +1,20 @@
+#if !defined(_STDBOOL_H) || defined(__LIBC_GUARDLESS_INCLUDE)
+
+#ifndef __cplusplus
+#  define bool _Bool
+
+#  define true 1
+#  define false 0
+#endif
+
 #ifndef _STDBOOL_H
-#define _STDBOOL_H 1
-
-#define bool _Bool
-
-#define true 1
-#define false 0
 
 #define __bool_true_false_are_defined 1
 
 #endif
+
+#if !defined(__LIBC_GUARDLESS_INCLUDE)
+#define _STDBOOL_H 1
+#endif
+
+#endif

stddef.h

@@ -1,5 +1,4 @@
-#ifndef _STDDEF_H
-#define _STDDEF_H 1
+#if !defined(_STDDEF_H) || defined(__LIBC_GUARDLESS_INCLUDE)
 
 typedef __SIZE_TYPE__ size_t;
 typedef __PTRDIFF_TYPE__ ptrdiff_t;
@@ -8,6 +7,14 @@ typedef __PTRDIFF_TYPE__ ptrdiff_t;
 typedef __WCHAR_TYPE__ wchar_t;
 #endif
 
+#ifdef __cplusplus
+typedef decltype(nullptr) nullptr_t;
+
+enum class byte : unsigned char {};
+#endif
+
+#ifndef _STDDEF_H
+
 #ifdef NULL
 #undef NULL
 #endif
@@ -21,3 +28,9 @@ typedef __WCHAR_TYPE__ wchar_t;
 #define offsetof(s, m) __builtin_offsetof(s, m)
 
 #endif
+
+#if !defined(__LIBC_GUARDLESS_INCLUDE)
+#define _STDDEF_H 1
+#endif
+
+#endif

stdint.h

@@ -1,5 +1,4 @@
-#ifndef _STDINT_H
-#define _STDINT_H 1
+#if !defined(_STDINT_H) || defined(__LIBC_GUARDLESS_INCLUDE)
 
 typedef __UINT8_TYPE__ uint8_t;
 typedef __UINT16_TYPE__ uint16_t;
@@ -37,6 +36,8 @@ typedef __INTPTR_TYPE__ intptr_t;
 typedef __UINTMAX_TYPE__ uintmax_t;
 typedef __INTMAX_TYPE__ intmax_t;
 
+#ifndef _STDINT_H
+
 /* Clang and GCC have different mechanisms for INT32_C and friends. */
 #ifdef __clang__
 #   define __LIBC_C_EXPAND_JOIN(x, suffix) x ## suffix
@@ -137,3 +138,9 @@ typedef __INTMAX_TYPE__ intmax_t;
 #define WINT_MIN (-WINT_MAX - 1)
 
 #endif
+
+#if !defined(__LIBC_GUARDLESS_INCLUDE)
+#define _STDINT_H 1
+#endif
+
+#endif