diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 7c1508c75..5c924b34d 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -10,6 +10,7 @@ include(mig)
 include(pyc)
 
 # Force linker settings to match 3.30.5 behavior
+# Apple's ld64 in cctools does not support the `--dependency-file` flag
 set(CMAKE_CXX_LINKER_DEPFILE_SUPPORTED FALSE)
 set(CMAKE_C_LINKER_DEPFILE_SUPPORTED FALSE)
 set(CMAKE_CXX_LINK_DEPENDS_USE_LINKER FALSE)