allow clang to build tailcall vm on windows, use __preserve_none for Call VM if available

Author: henderkes

Zend/zend_portability.h

@@ -346,7 +346,11 @@ char *alloca();
 #endif
 
 #ifdef HAVE_PRESERVE_NONE
-# define ZEND_PRESERVE_NONE __attribute__((preserve_none))
+# if defined(_MSC_VER) && !defined(__clang__)
+#  define ZEND_PRESERVE_NONE __preserve_none
+# else
+#  define ZEND_PRESERVE_NONE __attribute__((preserve_none))
+# endif
 #endif
 
 

Zend/zend_vm_opcodes.h

@@ -3362,6 +3362,10 @@ function toolset_setup_common_cflags()
 		}
 
 		ADD_FLAG("CFLAGS", "/Zc:wchar_t");
+
+		if (VCVERS >= 1944 && TARGET_ARCH === 'x64') {
+			AC_DEFINE('HAVE_PRESERVE_NONE', 1, 'Whether the compiler supports __preserve_none');
+		}
 	} else if (CLANG_TOOLSET) {
 		ADD_FLAG("CFLAGS", "-Wno-deprecated-declarations");
 		if (TARGET_ARCH == 'x86') {
@@ -3376,7 +3380,11 @@ function toolset_setup_common_cflags()
 
 		var vc_ver = probe_binary(PATH_PROG('cl', null));
 		ADD_FLAG("CFLAGS"," -fms-compatibility -fms-compatibility-version=" + vc_ver + " -fms-extensions");
-	}
+
+        if (CLANGVERS >= 1900 && (TARGET_ARCH === 'x64' || TARGET_ARCH === 'arm64')) {
+            AC_DEFINE('HAVE_PRESERVE_NONE', 1, 'Whether the compiler supports __attribute__((preserve_none))');
+        }
+    }
 
 	if (!CLANG_TOOLSET) {
 		/* clang uses __builtin_*() instead */