Pull in r144505 from upstream clang trunk:

Fix the signature of the getcontext builtin, eliminating incorrect
warnings about its prototype.

This also adds a -W(no-)builtin-requires-header option, which can be
used to enable or disable warnings of this kind.

MFC after:	1 week

1 files changed, 18 insertions, 0 deletions

diff --git a/contrib/llvm/tools/clang/lib/Serialization/ASTReader.cpp b/contrib/llvm/tools/clang/lib/Serialization/ASTReader.cpp
index fe1cc30..de19d85 100644
--- a/contrib/llvm/tools/clang/lib/Serialization/ASTReader.cpp
+++ b/contrib/llvm/tools/clang/lib/Serialization/ASTReader.cpp
@@ -2659,6 +2659,24 @@ void ASTReader::InitializeContext() {
       if (Context.ObjCSelRedefinitionType.isNull())
         Context.ObjCSelRedefinitionType = GetType(ObjCSelRedef);
     }
+
+    if (unsigned Ucontext_t = SpecialTypes[SPECIAL_TYPE_UCONTEXT_T]) {
+      QualType Ucontext_tType = GetType(Ucontext_t);
+      if (Ucontext_tType.isNull()) {
+        Error("ucontext_t type is NULL");
+        return;
+      }
+
+      if (!Context.ucontext_tDecl) {
+        if (const TypedefType *Typedef = Ucontext_tType->getAs<TypedefType>())
+          Context.setucontext_tDecl(Typedef->getDecl());
+        else {
+          const TagType *Tag = Ucontext_tType->getAs<TagType>();
+          assert(Tag && "Invalid ucontext_t type in AST file");
+          Context.setucontext_tDecl(Tag->getDecl());
+        }
+      }
+    }
   }
   
   ReadPragmaDiagnosticMappings(Context.getDiagnostics());