diff -up libdap-3.11.1/ResponseBuilder.cc.gcc47 libdap-3.11.1/ResponseBuilder.cc
--- libdap-3.11.1/ResponseBuilder.cc.gcc47	2011-04-29 07:19:43.000000000 -0600
+++ libdap-3.11.1/ResponseBuilder.cc	2012-01-14 08:50:16.434627257 -0700
@@ -27,6 +27,7 @@
 static char rcsid[] not_used = { "$Id: ResponseBuilder.cc 23477 2010-09-02 21:02:59Z jimg $" };
 
 #include <signal.h>
+#include <unistd.h>
 
 #ifndef WIN32
 // #include <unistd.h>   // for getopt