emacs-28 e6c2a2497d: Update from gnulib

[Mattias Engdegård]

branch: emacs-28
commit e6c2a2497d8cc8c38c816507681d5d529cfdbf2e
Author: Paul Eggert <eggert@cs.ucla.edu>
Commit: Mattias Engdegård <mattiase@acm.org>

    Update from gnulib
    
    (cherry picked from commit 992cf3cb675e074079341cc54c3b16d37a8b9ca8)
    
    This is a partial backport from master: it only includes the changes below.
    
    * lib/mini-gmp.c (gmp_assert_nocarry): Avoid many Clang
    unused-variable warnings when building with optimisation.
    * lib/verify.h (_GL_HAVE__STATIC_ASSERT): Modify condition for using
    _Static_assert to cope with older Apple builds of Clang exposing
    misleading compiler version numbers.  See discussion starting at
    https://lists.gnu.org/archive/html/emacs-devel/2022-04/msg00779.html
---
 lib/mini-gmp.c | 1 +
 lib/verify.h   | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/lib/mini-gmp.c b/lib/mini-gmp.c
index 8577b59ef6..14cabd1231 100644
--- a/lib/mini-gmp.c
+++ b/lib/mini-gmp.c
@@ -90,6 +90,7 @@ see https://www.gnu.org/licenses/.  */
 #define gmp_assert_nocarry(x) do { \
     mp_limb_t __cy = (x);         \
     assert (__cy == 0);                   \
+    (void) (__cy);                \
   } while (0)
 
 #define gmp_clz(count, x) do {                                         \
diff --git a/lib/verify.h b/lib/verify.h
index 07b2f4866f..c2d2a56670 100644
--- a/lib/verify.h
+++ b/lib/verify.h
@@ -34,7 +34,7 @@
 #ifndef __cplusplus
 # if (201112L <= __STDC_VERSION__ \
       || (!defined __STRICT_ANSI__ \
-          && (4 < __GNUC__ + (6 <= __GNUC_MINOR__) || 4 <= __clang_major__)))
+          && (4 < __GNUC__ + (6 <= __GNUC_MINOR__) || 5 <= __clang_major__)))
 #  define _GL_HAVE__STATIC_ASSERT 1
 # endif
 # if (202000L <= __STDC_VERSION__ \