dfa: Avoid warnings with some Apple clang versions.

Reported by Werner Lemberg <wl@gnu.org> in
<https://lists.gnu.org/archive/html/bug-gnulib/2023-02/msg00159.html>.

* lib/dfa.c (FALLTHROUGH): When __apple_build_version__ is defined,
ignore __clang_major__.

2 files changed, 12 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 3d8446ce5c..9477335e75 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2023-02-26  Bruno Haible  <bruno@clisp.org>
+
+	dfa: Avoid warnings with some Apple clang versions.
+	Reported by Werner Lemberg <wl@gnu.org> in
+	<https://lists.gnu.org/archive/html/bug-gnulib/2023-02/msg00159.html>.
+	* lib/dfa.c (FALLTHROUGH): When __apple_build_version__ is defined,
+	ignore __clang_major__.
+
 2023-02-25  Jim Meyering  <meyering@fb.com>
 
 	announce-gen: add more info the auto-generated announce template
diff --git a/lib/dfa.c b/lib/dfa.c
index 211e1ed18f..994900fea2 100644
--- a/lib/dfa.c
+++ b/lib/dfa.c
@@ -67,7 +67,10 @@ c_isdigit (char c)
 #ifndef FALLTHROUGH
 # if 201710L < __STDC_VERSION__
 #  define FALLTHROUGH [[__fallthrough__]]
-# elif (__GNUC__ >= 7) || (__clang_major__ >= 10)
+# elif ((__GNUC__ >= 7) \
+        || (defined __apple_build_version__ \
+            ? __apple_build_version__ >= 14000000 \
+            : __clang_major__ >= 10))
 #  define FALLTHROUGH __attribute__ ((__fallthrough__))
 # else
 #  define FALLTHROUGH ((void) 0)