ARRAYELTS → countof

C2y will standardize countof as the macro that Emacs uses the name
ARRAYELTS for.  Switch to the standard name, which is supported
by GCC 16+, by Clang 21, and by the Gnulib stdcountof-h module already
in use for compilers that do not support countof.
Also, use countof in a few places where we missed using ARRAYELTS.
* admin/coccinelle/arrayelts.cocci: Suggest countof, not ARRAYELTS.
* admin/merge-gnulib (GNULIB_MODULES): Add stdcountof-h,
as it is now a direct rather than an indirect dependency.
* exec/trace.c, src/lisp.h, src/sfnt.c: Include <stdcountof.h>.
(ARRAYELTS): Remove.  All uses replaced by countof.
* lib-src/ebrowse.c, lib-src/etags.c, lib-src/make-docfile.c:
* lib-src/seccomp-filter.c, lwlib/lwlib-Xaw.c:
Prefer <stdcountof.h> and countof to doing things by hand.

4 files changed, 9 insertions, 4 deletions

diff --git a/lib-src/ebrowse.c b/lib-src/ebrowse.c
index 3bb6bd88d79..93c0b52b950 100644
--- a/lib-src/ebrowse.c
+++ b/lib-src/ebrowse.c
@@ -19,6 +19,8 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 
 
 #include <config.h>
+
+#include <stdcountof.h>
 #include <stddef.h>
 #include <stdlib.h>
 #include <string.h>
@@ -3612,7 +3614,7 @@ static _Noreturn void
 usage (int error)
 {
   int i;
-  for (i = 0; i < sizeof usage_message / sizeof *usage_message; i++)
+  for (i = 0; i < countof (usage_message); i++)
     fputs (usage_message[i], stdout);
   exit (error ? EXIT_FAILURE : EXIT_SUCCESS);
 }
diff --git a/lib-src/etags.c b/lib-src/etags.c
index 4114ba6b655..977484e4a67 100644
--- a/lib-src/etags.c
+++ b/lib-src/etags.c
@@ -110,6 +110,7 @@ University of California, as described above. */
 #include <unistd.h>
 #include <stdarg.h>
 #include <stdckdint.h>
+#include <stdcountof.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sysstdio.h>
@@ -6693,7 +6694,7 @@ mercury_decl (char *s, size_t pos)
     }
   else
     {
-      for (int j = 0; j < sizeof (Mercury_decl_tags) / sizeof (char*); ++j)
+      for (int j = 0; j < countof (Mercury_decl_tags); ++j)
 	{
 	  if (memstreq (decl_type, decl_type_length, Mercury_decl_tags[j]))
 	    {
diff --git a/lib-src/make-docfile.c b/lib-src/make-docfile.c
index f6e321d876a..f13ade84244 100644
--- a/lib-src/make-docfile.c
+++ b/lib-src/make-docfile.c
@@ -37,6 +37,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 #include <config.h>
 
 #include <stdarg.h>
+#include <stdcountof.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <stdlib.h>
@@ -651,7 +652,7 @@ compare_globals (const void *a, const void *b)
       /* Common symbols in decreasing popularity order.  */
       static char const commonsym[][8]
 	= { "nil", "t", "unbound", "error", "lambda" };
-      int ncommonsym = sizeof commonsym / sizeof *commonsym;
+      int ncommonsym = countof (commonsym);
       int ai = ncommonsym, bi = ncommonsym;
       for (int i = 0; i < ncommonsym; i++)
 	{
diff --git a/lib-src/seccomp-filter.c b/lib-src/seccomp-filter.c
index a8cdc6e06f9..f58afbf272d 100644
--- a/lib-src/seccomp-filter.c
+++ b/lib-src/seccomp-filter.c
@@ -39,6 +39,7 @@ variants of those files that can be used to sandbox Emacs before
 #include <errno.h>
 #include <limits.h>
 #include <stdarg.h>
+#include <stdcountof.h>
 #include <stdlib.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -119,7 +120,7 @@ set_attribute (enum scmp_filter_attr attr, uint32_t value)
   do                                                                 \
     {                                                                \
       const struct scmp_arg_cmp arg_array[] = {__VA_ARGS__};         \
-      enum { arg_cnt = sizeof arg_array / sizeof *arg_array };       \
+      enum { arg_cnt = countof (arg_array) };			     \
       int status = seccomp_rule_add_array (ctx, action, syscall,     \
                                            arg_cnt, arg_array);      \
       if (status < 0)                                                \