diff --git a/Modules/ExternalProject.cmake b/Modules/ExternalProject.cmake
index a37771b929..fb55d3bf38 100644
--- a/Modules/ExternalProject.cmake
+++ b/Modules/ExternalProject.cmake
@@ -144,7 +144,7 @@
 #   set_property(DIRECTORY PROPERTY EP_STEP_TARGETS configure build test)
 
 #=============================================================================
-# Copyright 2008-2009 Kitware, Inc.
+# Copyright 2008-2012 Kitware, Inc.
 #
 # Distributed under the OSI-approved BSD License (the "License");
 # see accompanying file Copyright.txt for details.
@@ -954,6 +954,7 @@ function(_ep_get_git_version git_EXECUTABLE git_version_var)
     execute_process(
       COMMAND "${git_EXECUTABLE}" --version
       OUTPUT_VARIABLE ov
+      ERROR_VARIABLE ev
       OUTPUT_STRIP_TRAILING_WHITESPACE
       )
     string(REGEX REPLACE "^git version (.+)$" "\\1" version "${ov}")