diff -Naur clang-3.1.src-orig/lib/Driver/ToolChains.cpp clang-3.1.src/lib/Driver/ToolChains.cpp
--- clang-3.1.src-orig/lib/Driver/ToolChains.cpp	2012-05-11 20:16:02.000000000 -0400
+++ clang-3.1.src/lib/Driver/ToolChains.cpp	2012-10-08 01:13:01.044083509 -0400
@@ -2146,9 +2146,6 @@
   if (DriverArgs.hasArg(options::OPT_nostdinc))
     return;
 
-  if (!DriverArgs.hasArg(options::OPT_nostdlibinc))
-    addSystemInclude(DriverArgs, CC1Args, D.SysRoot + "/usr/local/include");
-
   if (!DriverArgs.hasArg(options::OPT_nobuiltininc)) {
     llvm::sys::Path P(D.ResourceDir);
     P.appendComponent("include");
@@ -2264,6 +2261,7 @@
     return;
 
   // Check if libc++ has been enabled and provide its include paths if so.
+  // !!! Will need to modify this if/when nixpkgs uses libc++
   if (GetCXXStdlibType(DriverArgs) == ToolChain::CST_Libcxx) {
     // libc++ is always installed at a fixed path on Linux currently.
     addSystemInclude(DriverArgs, CC1Args,