diff --git a/external/external_python_build.cmake b/external/external_python_build.cmake
index 9e94758..92ca65f 100644
--- a/external/external_python_build.cmake
+++ b/external/external_python_build.cmake
@@ -27,14 +27,19 @@ MESSAGE(STATUS "Python is installing its packages in ${PYTHON_LOCAL_SITE_PACKAGE
 
 
 IF(INTERNAL_CYTHON)
+  SET(BUILD_ENVIRONMENT 
+          ${CMAKE_COMMAND}
+           "-DPYTHON_EXECUTABLE=${PYTHON_EXECUTABLE}"
+           "-DPYTHON_LOCAL_SITE_PACKAGE=${PYTHON_LOCAL_SITE_PACKAGE}"
+           "-DTARGET_PATH=${CMAKE_BINARY_DIR}/ext_build/python" "-P") 
   ExternalProject_Add(cython
     DEPENDS ${PREV_PYTHON_BUILD}
     URL ${CYTHON_URL}
     PREFIX ${BUILD_PREFIX}/cython-prefix
     CONFIGURE_COMMAND echo "No configure"
     BUILD_IN_SOURCE 1
-    BUILD_COMMAND ${PYTHON_EXECUTABLE} setup.py build
-    INSTALL_COMMAND ${PYTHON_EXECUTABLE} setup.py install --prefix=${CMAKE_BINARY_DIR}/ext_build/python
+    BUILD_COMMAND ${BUILD_ENVIRONMENT} ${CMAKE_SOURCE_DIR}/external/python_build.cmake
+    INSTALL_COMMAND ${BUILD_ENVIRONMENT} ${CMAKE_SOURCE_DIR}/external/python_install.cmake
   ) 
   SET(PREV_PYTHON_BUILD ${PREV_PYTHON_BUILD} cython)
 ENDIF(INTERNAL_CYTHON)
diff --git a/external/python_build.cmake b/external/python_build.cmake
index 2359baa..f3de8de 100644
--- a/external/python_build.cmake
+++ b/external/python_build.cmake
@@ -4,8 +4,10 @@ SET(ENV{CPPFLAGS} ${PYTHON_CPPFLAGS})
 SET(ENV{LDFLAGS} ${PYTHON_LDFLAGS})
 SET(ENV{VOID_GSL} ${VOID_GSL})
 SET(ENV{PYTHONPATH} ${PYTHON_LOCAL_SITE_PACKAGE}:$ENV{PYTHONPATH})
+SET(PYTHON_BUILD_COMMAND ${PYTHON_EXECUTABLE} setup.py build)
+MESSAGE(STATUS "Running ${PYTHON_BUILD_COMMAND}")
 execute_process(
-  COMMAND ${PYTHON_EXECUTABLE} setup.py build
+  COMMAND ${PYTHON_BUILD_COMMAND}
   RESULT_VARIABLE RET_VALUE
 )
 
diff --git a/external/python_install.cmake b/external/python_install.cmake
index f156b24..5afa3cb 100644
--- a/external/python_install.cmake
+++ b/external/python_install.cmake
@@ -4,8 +4,10 @@ SET(ENV{CPPFLAGS} ${PYTHON_CPPFLAGS})
 SET(ENV{LDFLAGS} ${PYTHON_LDFLAGS})
 SET(ENV{VOID_GSL} ${VOID_GSL})
 SET(ENV{PYTHONPATH} ${PYTHON_LOCAL_SITE_PACKAGE}:$ENV{PYTHONPATH})
+SET(PYTHON_INSTALL_COMMAND ${PYTHON_EXECUTABLE} setup.py install --prefix=${TARGET_PATH} --install-lib=${PYTHON_LOCAL_SITE_PACKAGE})
+message(STATUS "Running ${PYTHON_INSTALL_COMMAND}")
 execute_process(
-  COMMAND ${PYTHON_EXECUTABLE} setup.py install --prefix=${TARGET_PATH}
+  COMMAND ${PYTHON_INSTALL_COMMAND}
   RESULT_VARIABLE RET_VALUE
 )