Merge pull request #202 from NervanaSystems/yixing/cmake_install

NGRAPH_INSTALL_PREFIX instead of CMAKE_INSTALL_PREFIX

src/ngraph/CMakeLists.txt

@@ -121,9 +121,13 @@ endif()
 # won't override artifacts generated by other users.
 #
 # The user can always override this by using the cmake command listed below.
-set(CMAKE_INSTALL_PREFIX "$ENV{HOME}/ngraph_dist" CACHE PATH "Install directory" FORCE)
+if (NGRAPH_INSTALL_PREFIX)
+    set(CMAKE_INSTALL_PREFIX ${NGRAPH_INSTALL_PREFIX})
+else()
+    set(CMAKE_INSTALL_PREFIX "$ENV{HOME}/ngraph_dist")
+endif()
 message (STATUS "Installation directory: ${CMAKE_INSTALL_PREFIX}")
-message (STATUS "To Override use: cmake -DCMAKE_INSTALL_PREFIX=/foo -P cmake_install.cmake")
+message (STATUS "To Override use: cmake -DNGRAPH_INSTALL_PREFIX=/foo")
 
 # Destinations
 set(CMAKE_INSTALL_LIB "${CMAKE_INSTALL_PREFIX}/lib")