Introduce the notion of excluded headers into the module map
description. Previously, one could emulate this behavior by placing
the header in an always-unavailable submodule, but Argyrios guilted me
into expressing this idea properly.

llvm-svn: 165921
diff --git a/clang/lib/Basic/Module.cpp b/clang/lib/Basic/Module.cpp
index 91b6207..76c7f8b 100644
--- a/clang/lib/Basic/Module.cpp
+++ b/clang/lib/Basic/Module.cpp
@@ -219,6 +219,13 @@
     OS.write_escaped(Headers[I]->getName());
     OS << "\"\n";
   }
+
+  for (unsigned I = 0, N = ExcludedHeaders.size(); I != N; ++I) {
+    OS.indent(Indent + 2);
+    OS << "exclude header \"";
+    OS.write_escaped(ExcludedHeaders[I]->getName());
+    OS << "\"\n";
+  }
   
   for (submodule_const_iterator MI = submodule_begin(), MIEnd = submodule_end();
        MI != MIEnd; ++MI)