Sort file lists

to enable more reproducible builds
without patching individual build definitions

Help/release/dev/sorted-glob.rst

+sorted glob
+-----------
+
+* calls like `file(GLOB SOMEVARIABLE "*.c")`
+  will now return sorted results on POSIX-compliant platforms
+  to avoid builds that order functions in output files depending on
+  random filesystem order

Source/kwsys/Directory.cxx

@@ -201,17 +201,21 @@ bool Directory::Load(const std::string& name)
 {
   this->Clear();
 
-  DIR* dir = opendir(name.c_str());
+  kwsys_dirent** namelist;
+  int n;
+  n = scandir(name.c_str(), &namelist, NULL, alphasort);
 
-  if (!dir) {
+  if (n == -1) {
     return 0;
   }
 
-  for (kwsys_dirent* d = readdir(dir); d; d = readdir(dir)) {
+  while ( n-- ) {
+    kwsys_dirent* d = namelist[n];
     this->Internal->Files.push_back(d->d_name);
+    free(d);
   }
   this->Internal->Path = name;
-  closedir(dir);
+  free(namelist);
   return 1;
 }