NFC: Remove the ObjC1/ObjC2 distinction from clang (and related projects)

We haven't supported compiling ObjC1 for a long time (and never will again), so
there isn't any reason to keep these separate. This patch replaces
LangOpts::ObjC1 and LangOpts::ObjC2 with LangOpts::ObjC.

Differential revision: https://reviews.llvm.org/D53547

llvm-svn: 345637
diff --git a/clang/lib/Parse/ParseStmt.cpp b/clang/lib/Parse/ParseStmt.cpp
index ba7c808..8461ee1 100644
--- a/clang/lib/Parse/ParseStmt.cpp
+++ b/clang/lib/Parse/ParseStmt.cpp
@@ -1542,7 +1542,7 @@
   }
 
   bool C99orCXXorObjC = getLangOpts().C99 || getLangOpts().CPlusPlus ||
-    getLangOpts().ObjC1;
+    getLangOpts().ObjC;
 
   // C99 6.8.5p5 - In C99, the for statement is a block.  This is not
   // the case for C90.  Start the loop scope.