From a73391327e9226caafed7b64c0896d7bb0bc4fdb Mon Sep 17 00:00:00 2001
From: David Griffith <dave@661.org>
Date: Tue, 20 Feb 2018 03:37:50 -0800
Subject: [PATCH] Add workarounds for compilers that lack the fallthrough
 attribute.

---
 src/common/frotz.h   | 14 ++++++++++++++
 src/common/quetzal.c |  4 ++--
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/common/frotz.h b/src/common/frotz.h
index 5794e4b..7103e53 100644
--- a/src/common/frotz.h
+++ b/src/common/frotz.h
@@ -46,6 +46,20 @@ typedef int bool;
 #define PATH_SEPARATOR '/'
 #endif
 
+
+#ifndef __has_c_attribute	/* Optional */
+#define __has_c_attribute(x) 0	/* Compat with non-clang compilers */
+#endif
+
+#if __has_c_attribute(fallthrough)
+#define FALLTHROUGH [[fallthrough]]
+#elif  __GNUC__ >= 7
+#define FALLTHROUGH   __attribute__((fallthrough))
+#else
+#define FALLTHROUGH
+#endif
+
+
 /* typedef unsigned short zbyte; */
 typedef unsigned char zbyte;
 typedef unsigned short zword;
diff --git a/src/common/quetzal.c b/src/common/quetzal.c
index c399559..459fe3e 100644
--- a/src/common/quetzal.c
+++ b/src/common/quetzal.c
@@ -377,7 +377,7 @@ zword restore_quetzal (FILE *svf, FILE *stf)
 		    break;
 	    }
 		/* Fall right thru (to default) if already GOT_MEMORY */
-		__attribute__((fallthrough));
+		FALLTHROUGH;
 	    /* `UMem' uncompressed memory chunk; load it. */
 	    case ID_UMem:
 		if (!(progress & GOT_MEMORY))	/* Don't complain if two. */
@@ -396,7 +396,7 @@ zword restore_quetzal (FILE *svf, FILE *stf)
 		    /* Fall into default action (skip chunk) on errors. */
 		}
 		/* Fall thru (to default) if already GOT_MEMORY */
-		__attribute__((fallthrough));
+		FALLTHROUGH;
 	    /* Unrecognised chunk type; skip it. */
 	    default:
 		(void) fseek (svf, currlen, SEEK_CUR);	/* Skip chunk. */
-- 
2.34.1