Rename DeclContext::getLookupContext to getRedeclContext and change its semantics slightly. No functionality change in the absence of inline namespaces. Also, change a few places where inline namespaces actually make a difference to be prepared for them.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@112563 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaDeclObjC.cpp b/lib/Sema/SemaDeclObjC.cpp
index ac9d076..3c6f224 100644
--- a/lib/Sema/SemaDeclObjC.cpp
+++ b/lib/Sema/SemaDeclObjC.cpp
@@ -1626,7 +1626,7 @@
 }
 
 bool Sema::CheckObjCDeclScope(Decl *D) {
-  if (isa<TranslationUnitDecl>(CurContext->getLookupContext()))
+  if (isa<TranslationUnitDecl>(CurContext->getRedeclContext()))
     return false;
 
   Diag(D->getLocation(), diag::err_objc_decls_may_only_appear_in_global_scope);