diff -ru -x '*~' a/tools/clang/lib/Frontend/InitHeaderSearch.cpp b/tools/clang/lib/Frontend/InitHeaderSearch.cpp
--- a/tools/clang/lib/Frontend/InitHeaderSearch.cpp	2011-03-21 20:24:04.000000000 -0400
+++ b/tools/clang/lib/Frontend/InitHeaderSearch.cpp	2011-10-18 12:09:50.624355551 -0400
@@ -438,6 +438,7 @@
 
 void InitHeaderSearch::AddDefaultCIncludePaths(const llvm::Triple &triple,
                                             const HeaderSearchOptions &HSOpts) {
+#if 0
   llvm::Triple::OSType os = triple.getOS();
 
   switch (os) {
@@ -559,6 +560,8 @@
   }
 
   AddPath("/usr/include", System, false, false, false);
+#endif
+  AddPath(C_INCLUDE_PATH, System, false, false, false);
 }
 
 void InitHeaderSearch::
@@ -577,6 +580,7 @@
                                   triple);
     return;
   }
+#if 0  
   // FIXME: temporary hack: hard-coded paths.
   switch (os) {
   case llvm::Triple::Cygwin:
@@ -847,6 +851,10 @@
   default:
     break;
   }
+#endif
+  AddGnuCPlusPlusIncludePaths(
+      CPP_INCLUDE_PATH,
+      CPP_HOST, "", "", triple);
 }
 
 void InitHeaderSearch::AddDefaultSystemIncludePaths(const LangOptions &Lang,