From 0e934c7df1aa82e72dfb3654e8f0f3a42bad9f01 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20R=C3=B8nne=20Petersen?= <alex@alexrp.com>
Date: Mon, 2 Dec 2024 09:42:39 +0100
Subject: [PATCH] zig.h: Use C99/C11 headers if available regardless of
 language standard.

If present, these headers are usable even when compiling for older C language
versions.

Most notably, this enables zig.h atomics to work with slimcc and TinyCC in C99
mode (and earlier).
---
 lib/zig.h | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/lib/zig.h b/lib/zig.h
index 06d44fe819..f1fc5ebfdd 100644
--- a/lib/zig.h
+++ b/lib/zig.h
@@ -68,9 +68,16 @@
 #define zig_x86
 #endif
 
+#if defined(__has_include)
+#define zig_has_include(include) __has_include(include)
+#else
+#define zig_has_include(include) 0
+#endif
+
 #ifndef __STDC_WANT_IEC_60559_TYPES_EXT__
 #define __STDC_WANT_IEC_60559_TYPES_EXT__
 #endif
+
 #include <float.h>
 #include <limits.h>
 #include <stdarg.h>
@@ -82,7 +89,7 @@
 
 #if __STDC_VERSION__ >= 202311L
 /* bool, true, and false are provided by the language. */
-#elif __STDC_VERSION__ >= 199901L
+#elif __STDC_VERSION__ >= 199901L || zig_has_include(<stdbool.h>)
 #include <stdbool.h>
 #else
 typedef char bool;
@@ -428,7 +435,7 @@ zig_extern void *memset (void *, int, size_t);
 
 /* ===================== 8/16/32/64-bit Integer Support ===================== */
 
-#if __STDC_VERSION__ >= 199901L || defined(zig_msvc)
+#if __STDC_VERSION__ >= 199901L || defined(zig_msvc) || zig_has_include(<stdint.h>)
 #include <stdint.h>
 #else
 
@@ -3655,7 +3662,7 @@ zig_float_builtins(64)
     res = zig_atomicrmw_expected; \
 } while (0)
 
-#if __STDC_VERSION__ >= 201112L && !defined(__STDC_NO_ATOMICS__)
+#if (__STDC_VERSION__ >= 201112L || (zig_has_include(<stdatomic.h>) && !defined(zig_msvc))) && !defined(__STDC_NO_ATOMICS__)
 #include <stdatomic.h>
 typedef enum memory_order zig_memory_order;
 #define zig_memory_order_relaxed memory_order_relaxed