bug#60326: [COMMITTED 8/8] gzip: port alignas usage to C23

[Paul Eggert]

* gzip.c (BUFFER_ALIGNED): Do not depend on __alignas_is_defined
as that has been removed from C23.
---
 NEWS   | 2 +-
 gzip.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/NEWS b/NEWS
index 918fcf2..f2ea30e 100644
--- a/NEWS
+++ b/NEWS
@@ -9,7 +9,7 @@ GNU gzip NEWS                                    -*- outline -*-
   [bug present since the beginning]
 
   Port to C23, which does not allow K&R-style function definitions
-  with parameters.
+  with parameters, and which does not define __alignas_is_defined.
 
 
 * Noteworthy changes in release 1.12 (2022-04-07) [stable]
diff --git a/gzip.c b/gzip.c
index fcf8e06..5cfdb24 100644
--- a/gzip.c
+++ b/gzip.c
@@ -134,7 +134,7 @@ static char const *const license_msg[] = {
    windows; the alignment requirement is 4096.  On other platforms
    alignment doesn't hurt, and alignment up to 4096 is portable so
    let's do that.  */
-#ifdef __alignas_is_defined
+#if defined HAVE_C_ALIGNASOF || defined alignas
 # define BUFFER_ALIGNED alignas (4096)
 #else
 # define BUFFER_ALIGNED /**/
-- 
2.38.1