Implement -fgnu89-inline. Fixes PR10041.

llvm-svn: 132460
diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index f5b6421..d77bda7 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -1527,7 +1527,7 @@
 /// GNU89 mode.
 static bool canRedefineFunction(const FunctionDecl *FD,
                                 const LangOptions& LangOpts) {
-  return (LangOpts.GNUMode && !LangOpts.C99 && !LangOpts.CPlusPlus &&
+  return (LangOpts.GNUInline && !LangOpts.CPlusPlus &&
           FD->isInlineSpecified() &&
           FD->getStorageClass() == SC_Extern);
 }