diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0d4e5b69..78c72f8f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -12,7 +12,7 @@ set(LUNA_BASE ${CMAKE_CURRENT_LIST_DIR}/base)
 
 set(ARCH $ENV{ARCH})
 
-if(NOT DEFINED $ENV{ARCH})
+if(NOT DEFINED ARCH)
 set(ARCH "x86_64")
 endif()