memory: xstrchrnul and xmemscan.

src/nvim/os/fs.c

@@ -134,10 +134,7 @@ static bool is_executable_in_path(const char_u *name, char_u **abspath)
   // Walk through all entries in $PATH to check if "name" exists there and
   // is an executable file.
   for (;; ) {
-    const char *e = strchr(path, ':');
-    if (e == NULL) {
-      e = path + STRLEN(path);
-    }
+    const char *e = xstrchrnul(path, ':');
 
     // Glue together the given directory from $PATH with name and save into
     // buf.