stdckdint-h: new module

This supports draft C23 <stdckdint.h>.
* doc/posix-headers/stdckdint.texi:
* lib/stdckdint.in.h, modules/stdckdint:
* modules/stdckdint-tests, tests/test-stdckdint.c:
New files.
* MODULES.html.sh, doc/gnulib.texi: Update for new module.
* lib/intprops-internal.h: Include <stdckdint.h> if C23 and
its macros would help and our substitute has not already
started to be included.
(_GL_INT_ADD_WRAPV, _GL_INT_SUBTRACT_WRAPV)
(_GL_INT_MULTIPLY_WRAPV): Use ckd_add, ckd_sub, ckd_mul
if they are defined and would help.
* lib/intprops-internal.h, lib/intprops.h: Improve comments.
The C23 restrictions on stdckdint macros already mostly applied to
intprops.h, so these are clarifications, not further restrictions.
* tests/test-intprops.c: If TEST_STDCKDINT is defined,
include <stdckdint.h> instead of "intprops.h", and test
it instead.
(VERIFY) [TEST_STDCKDINT]: Ignore the arg in this case.
(main) [TEST_STDCKDINT]: Skip tests irrelevant to stdckdint.h.

1 files changed, 15 insertions, 0 deletions

diff --git a/modules/stdckdint-tests b/modules/stdckdint-tests
new file mode 100644
index 0000000000..153a1fbb42
--- /dev/null
+++ b/modules/stdckdint-tests
@@ -0,0 +1,15 @@
+Files:
+tests/macros.h
+tests/test-intprops.c
+tests/test-stdckdint.c
+
+Depends-on:
+inttypes
+stdbool
+verify
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-stdckdint
+check_PROGRAMS += test-stdckdint