Improve the specification of spellings in Attr.td.

Note that this is mostly a structural patch that handles the change from the old
spelling style to the new one. One consequence of this is that all AT_foo_bar
enum values have changed to not be based off of the first spelling, but rather
off of the class name, so they are now AT_FooBar and the like (a straw poll on
IRC showed support for this). Apologies for code churn.

Most attributes have GNU spellings as a temporary solution until everything else
is sorted out (such as a Keyword spelling, which I intend to add if someone else
doesn't beat me to it). This is definitely a WIP.

I've also killed BaseCheckAttr since it was unused, and I had to go through
every attribute anyway.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@158700 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Parse/ParseDeclCXX.cpp b/lib/Parse/ParseDeclCXX.cpp
index b906292..6e391c9 100644
--- a/lib/Parse/ParseDeclCXX.cpp
+++ b/lib/Parse/ParseDeclCXX.cpp
@@ -2902,11 +2902,11 @@
     switch (AttributeList::getKind(AttrName, ScopeName,
                                    AttributeList::AS_CXX11)) {
     // No arguments
-    case AttributeList::AT_carries_dependency:
+    case AttributeList::AT_CarriesDependency:
     // FIXME: implement generic support of attributes with C++11 syntax
     // see Parse/ParseDecl.cpp: ParseGNUAttributes
-    case AttributeList::AT_fallthrough:
-    case AttributeList::AT_noreturn: {
+    case AttributeList::AT_FallThrough:
+    case AttributeList::AT_NoReturn: {
       if (Tok.is(tok::l_paren)) {
         Diag(Tok.getLocation(), diag::err_cxx11_attribute_forbids_arguments)
           << AttrName->getName();