[PATCH 08 of 11] Support for Clang with "-fgnuc-version=0"

[Maxim Dounin]

# HG changeset patch
# User Maxim Dounin <mdounin at mdounin.ru>
# Date 1722992310 -10800
#      Wed Aug 07 03:58:30 2024 +0300
# Node ID d286426eab1a2953b27161829dbca27ce578c706
# Parent  32a5186a27058925bfa9280215ecee114a56d6be
Support for Clang with "-fgnuc-version=0".

Previously, the code assumed that Clang pretends to be GCC and defines
the __GNUC__ macro, which might not be the case if the "-fgnuc-version=0"
flag is used.  Fix is to explicitly check for __clang__ as well.

In practice, with this change ngx_cpuinfo() is now available on Linux
with "-fgnuc-version=0".

diff --git a/src/core/ngx_cpuinfo.c b/src/core/ngx_cpuinfo.c
--- a/src/core/ngx_cpuinfo.c
+++ b/src/core/ngx_cpuinfo.c
@@ -9,7 +9,8 @@
 #include <ngx_core.h>
 
 
-#if (( __i386__ || __amd64__ ) && ( __GNUC__ || __INTEL_COMPILER ))
+#if (( __i386__ || __amd64__ )                                                \
+    && ( __GNUC__ || __clang__ || __INTEL_COMPILER ))
 
 
 static ngx_inline void ngx_cpuid(uint32_t i, uint32_t *buf);
diff --git a/src/event/modules/ngx_iocp_module.c b/src/event/modules/ngx_iocp_module.c
--- a/src/event/modules/ngx_iocp_module.c
+++ b/src/event/modules/ngx_iocp_module.c
@@ -172,7 +172,7 @@ ngx_iocp_timer(void *data)
 #endif
     }
 
-#if defined(__WATCOMC__) || defined(__GNUC__)
+#if defined(__WATCOMC__) || defined(__GNUC__) || defined(__clang__)
     return 0;
 #endif
 }
diff --git a/src/os/unix/ngx_atomic.h b/src/os/unix/ngx_atomic.h
--- a/src/os/unix/ngx_atomic.h
+++ b/src/os/unix/ngx_atomic.h
@@ -153,7 +153,7 @@ ngx_cpu_pause(void);
 #define ngx_memory_barrier()        __asm (".volatile"); __asm (".nonvolatile")
 
 
-#else /* ( __GNUC__ || __INTEL_COMPILER ) */
+#else /* ( __GNUC__ || __clang__ || __INTEL_COMPILER ) */
 
 #define NGX_HAVE_ATOMIC_OPS  1
 
@@ -194,7 +194,7 @@ ngx_cpu_pause(void);
 #define ngx_memory_barrier()        __asm (".volatile"); __asm (".nonvolatile")
 
 
-#else /* ( __GNUC__ || __INTEL_COMPILER ) */
+#else /* ( __GNUC__ || __clang__ || __INTEL_COMPILER ) */
 
 #define NGX_HAVE_ATOMIC_OPS  1
 
@@ -229,7 +229,7 @@ typedef volatile ngx_atomic_uint_t  ngx_
 #include "ngx_sunpro_atomic_sparc64.h"
 
 
-#else /* ( __GNUC__ || __INTEL_COMPILER ) */
+#else /* ( __GNUC__ || __clang__ || __INTEL_COMPILER ) */
 
 #define NGX_HAVE_ATOMIC_OPS  1