Add additional note to mark the cause of synthesized constructors.  Mark
declaration invalid if the constructor can't be properly built.  Addresses
remaining review comments from Fariborz for r86500.

llvm-svn: 86579
diff --git a/clang/test/SemaCXX/value-initialization.cpp b/clang/test/SemaCXX/value-initialization.cpp
index 3452883..25d7084 100644
--- a/clang/test/SemaCXX/value-initialization.cpp
+++ b/clang/test/SemaCXX/value-initialization.cpp
@@ -6,5 +6,5 @@
 };
 
 int main () {
-      (void)A();
+      (void)A(); // expected-note {{first required here}}
 }