Introduce module attributes into the module map grammar, along with a
single attribute ("system") that allows us to mark a module as being a
"system" module. Each of the headers that makes up a system module is
considered to be a system header, so that we (for example) suppress
warnings there.

If a module is being inferred for a framework, and that framework
directory is within a system frameworks directory, infer it as a
system framework.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@149143 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Basic/Module.cpp b/lib/Basic/Module.cpp
index ff09441..015f421 100644
--- a/lib/Basic/Module.cpp
+++ b/lib/Basic/Module.cpp
@@ -24,9 +24,9 @@
                bool IsFramework, bool IsExplicit)
   : Name(Name), DefinitionLoc(DefinitionLoc), Parent(Parent), 
     Umbrella(), IsAvailable(true), IsFromModuleFile(false), 
-    IsFramework(IsFramework), IsExplicit(IsExplicit), InferSubmodules(false), 
-    InferExplicitSubmodules(false), InferExportWildcard(false),
-    NameVisibility(Hidden) 
+    IsFramework(IsFramework), IsExplicit(IsExplicit), IsSystem(false),
+    InferSubmodules(false), InferExplicitSubmodules(false), 
+    InferExportWildcard(false), NameVisibility(Hidden) 
 { 
   if (Parent) {
     if (!Parent->isAvailable())
@@ -172,8 +172,15 @@
     OS << "framework ";
   if (IsExplicit)
     OS << "explicit ";
-  OS << "module " << Name << " {\n";
+  OS << "module " << Name;
 
+  if (IsSystem) {
+    OS.indent(Indent + 2);
+    OS << " [system]";
+  }
+
+  OS << " {\n";
+  
   if (!Requires.empty()) {
     OS.indent(Indent + 2);
     OS << "requires ";