building/porting.md

@@ -2,6 +2,8 @@
 
 **NOTE**: Versions supported: 6.11+.
 
+**NOTE**: there are bugs in this procedure; see [\#3472](https://gitlab.haskell.org//ghc/ghc/issues/3472)
+
 
 This section describes how to port GHC to a currently
 unsupported platform.  To avoid confusion, when we say