diff --git a/math/carve/files/patch-external_gtest-1.5.0_include_gtest_internal_gtest-port.h b/math/carve/files/patch-external_gtest-1.5.0_include_gtest_internal_gtest-port.h
new file mode 100644
index 000000000000..69cabda0c409
--- /dev/null
+++ b/math/carve/files/patch-external_gtest-1.5.0_include_gtest_internal_gtest-port.h
@@ -0,0 +1,10 @@
+--- external/gtest-1.5.0/include/gtest/internal/gtest-port.h.orig	2011-08-26 20:16:23.000000000 +0000
++++ external/gtest-1.5.0/include/gtest/internal/gtest-port.h
+@@ -176,6 +176,7 @@
+ #ifndef _WIN32_WCE
+ #include <sys/stat.h>
+ #endif  // !_WIN32_WCE
++#include <unistd.h>
+ 
+ #include <iostream>  // NOLINT
+ #include <sstream>  // NOLINT