Index: README
==================================================================
--- README
+++ README
@@ -33,10 +33,14 @@
 
   To use the Mac OS X framework in Xcode, you need to add the .framework
   to your project and add the following flags to "Other C Flags":
 
     -fconstant-string-class=OFConstantString -fno-constant-cfstrings
+
+  Additionally, since Xcode 4, you need to manually set the compiler to GCC
+  or LLVM-GCC due to bugs in Clang on OS X with using a different constant
+  string class.
 
   Optionally, if you want to use blocks, you also need to add:
 
     -fblocks