diff -Nru tesseract-3.01.orig/viewer/svutil.cpp tesseract-3.01/viewer/svutil.cpp
--- tesseract-3.01.orig/viewer/svutil.cpp	2011-10-22 04:21:21.000000000 +0200
+++ tesseract-3.01/viewer/svutil.cpp	2012-07-14 16:26:43.184806273 +0200
@@ -21,6 +21,7 @@
 // thread/process creation & synchronization and network connection.
 
 #include <stdio.h>
+#include <unistd.h>
 #ifdef WIN32
 struct addrinfo {
   struct sockaddr* ai_addr;