Prefer PATH_MAX to MAXPATHLEN

PATH_MAX is standardized, MAXPATHLEN is not.
Also, the Gnulib pathmax module fixes some rare bugs with PATH_MAX.
So prefer PATH_MAX to MAXPATHLEN unless we know the latter is
also correct (for some platform-specific code).
* admin/merge-gnulib (GNULIB_MODULES): Add pathmax.
This module was already present, as a dependency of canonicalize-lgpl,
but now Emacs is using it directly.  Sort.
* lib-src/emacsclient.c: Include stdint.h, pathmax.h.
(get_current_dir_name): Sync to current src/sysdep.c.
* lib/gnulib.mk.in, m4/gnulib-comp.m4: Regenerate.
* src/sysdep.c: Include pathmax.h.
(get_current_dir_name_or_unreachable):
Use PATH_MAX instead of MAXPATHLEN.

1 files changed, 4 insertions, 3 deletions

diff --git a/src/sysdep.c b/src/sysdep.c
index b702bae5818..f7fc99f147f 100644
--- a/src/sysdep.c
+++ b/src/sysdep.c
@@ -30,6 +30,7 @@ along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */
 #include <unistd.h>
 
 #include <c-ctype.h>
+#include <pathmax.h>
 #include <utimens.h>
 
 #include "lisp.h"
@@ -262,10 +263,10 @@ get_current_dir_name_or_unreachable (void)
   ptrdiff_t dirsize_max = min (PTRDIFF_MAX, SIZE_MAX) - 1;
 
   /* The maximum size of a buffer for a file name, including the
-     terminating NUL.  This is bounded by MAXPATHLEN, if available.  */
+     terminating NUL.  This is bounded by PATH_MAX, if available.  */
   ptrdiff_t bufsize_max = dirsize_max;
-#ifdef MAXPATHLEN
-  bufsize_max = min (bufsize_max, MAXPATHLEN);
+#ifdef PATH_MAX
+  bufsize_max = min (bufsize_max, PATH_MAX);
 #endif
 
 # if HAVE_GET_CURRENT_DIR_NAME && !BROKEN_GET_CURRENT_DIR_NAME