diff --git a/cumulus/CMakeLists.txt b/cumulus/CMakeLists.txt
index 42030cb5..29dd414c 100644
--- a/cumulus/CMakeLists.txt
+++ b/cumulus/CMakeLists.txt
@@ -9,7 +9,7 @@
  
  set_cmake_policies()
  set_lib_link_mode()
- setup_sysconfdir("$ENV{CORIOLIS_TOP}")
+ setup_sysconfdir("${CMAKE_INSTALL_PREFIX}")
  
  find_package(PythonLibs REQUIRED)
  find_package(PythonSitePackages REQUIRED)