From c07e705c48a509898b8e1744eb0db3cf86508c86 Mon Sep 17 00:00:00 2001
From: hendricks266 <hendricks266@1a8010ca-5511-0410-912e-c29ae57300e0>
Date: Sat, 23 Sep 2017 03:17:29 +0000
Subject: [PATCH] Update fallthrough__ definitions.

git-svn-id: https://svn.eduke32.com/eduke32@6447 1a8010ca-5511-0410-912e-c29ae57300e0
---
 source/build/include/compat.h | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/source/build/include/compat.h b/source/build/include/compat.h
index 84cd37779..fefba2832 100644
--- a/source/build/include/compat.h
+++ b/source/build/include/compat.h
@@ -226,16 +226,23 @@
 # define CONSTEXPR_CXX14
 #endif
 
-#if __has_cpp_attribute(fallthrough)
-# define fallthrough__ [[fallthrough]]
-#elif __has_cpp_attribute(clang::fallthrough)
-# define fallthrough__ [[clang::fallthrough]]
-#elif __has_cpp_attribute(gnu::fallthrough)
-# define fallthrough__ [[gnu::fallthrough]]
-#elif defined _MSC_VER
-# define fallthrough__ __fallthrough
-#else
-# define fallthrough__
+#ifdef __cplusplus
+# if __has_cpp_attribute(fallthrough)
+#  define fallthrough__ [[fallthrough]]
+# elif __has_cpp_attribute(clang::fallthrough)
+#  define fallthrough__ [[clang::fallthrough]]
+# elif __has_cpp_attribute(gnu::fallthrough)
+#  define fallthrough__ [[gnu::fallthrough]]
+# endif
+#endif
+#ifndef fallthrough__
+# if !defined __clang__ && EDUKE32_GCC_PREREQ(7,0)
+#  define fallthrough__ __attribute__((fallthrough))
+# elif defined _MSC_VER
+#  define fallthrough__ __fallthrough
+# else
+#  define fallthrough__
+# endif
 #endif