add note
diff --git a/Misc/NEWS b/Misc/NEWS
index c78eaa8..a24267a 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -93,6 +93,9 @@
 Build
 -----
 
+- Issue #6943: Use pkg-config to find the libffi headers when the
+ --with-system-ffi flag is used.
+
 - Issue #7609: Add a --with-system-expat option that causes the system's expat
   library to be used for the pyexpat module instead of the one included with
   Python.