Implement AST importing of Objective-C instance variables. 
Check superclasses when merging two Objective-C @interfaces.

llvm-svn: 96420
diff --git a/clang/test/ASTMerge/Inputs/interface1.m b/clang/test/ASTMerge/Inputs/interface1.m
index 1aa1c3b..ebcd2bb 100644
--- a/clang/test/ASTMerge/Inputs/interface1.m
+++ b/clang/test/ASTMerge/Inputs/interface1.m
@@ -1,7 +1,23 @@
 // Matches
-@interface I1
+@interface I1 {
+  int ivar1;
+}
 @end
 
 // Matches
-@interface I2 : I1
+@interface I2 : I1 {
+  float ivar2;
+}
+@end
+
+// Ivar mismatch
+@interface I3 {
+  int ivar1;
+  int ivar2;
+}
+@end
+
+// Superclass mismatch
+@interface I4 : I2 {
+}
 @end