--- ldc-0.17.5-src.orig/runtime/phobos/etc/c/zlib/gzread.c	2018-05-14 14:41:28.022309026 +0200
+++ ldc-0.17.5-src/runtime/phobos/etc/c/zlib/gzread.c	2018-06-01 14:09:53.063607286 +0200
@@ -3,6 +3,7 @@
  * For conditions of distribution and use, see copyright notice in zlib.h
  */
 
+#include <unistd.h>
 #include "gzguts.h"
 
 /* Local functions */