https://sourceforge.net/p/toppler/bugs/18/
--- decl.cc.orig	2012-12-22 05:02:06.000000000 -0600
+++ decl.cc	2016-12-05 21:55:46.000000000 -0600
@@ -123,12 +123,12 @@
 
   DIR *d = opendir(n);
 
-  if (!d) {
+  if (d == NULL) {
     mkdir(n, S_IRWXU);
+  } else {
+    closedir(d);
   }
 
-  closedir(d);
-
   free(n);
 #endif