diff --git a/third_party/CMakeLists.txt b/third_party/CMakeLists.txt
index 412890b4a6d83f4ef4117b547bcc4d95cc28ec2b..3035309ec7ab7b4fa08d8b54f83bf0eeab7687e7 100644
--- a/third_party/CMakeLists.txt
+++ b/third_party/CMakeLists.txt
@@ -26,7 +26,7 @@ macro (luajit_build)
         set (luajit_copt ${luajit_copt} -O1)
         set (luajit_buildoptions ${luajit_buildoptions} XCFLAGS='-DLUA_USE_APICHECK -DLUA_USE_ASSERT')
     else ()
-	set (luajit_copt ${luajit_copt} -O2)
+        set (luajit_copt ${luajit_copt} -O2)
     endif()
     if (NOT HAVE_UNWIND_H)
         set (luajit_copt ${luajit_copt} -I${PROJECT_SOURCE_DIR}/third_party/compat)