Fix a couple of bugs, add some new cool stuff.

1. Fix a todo in Parser::ParseTag, to recover better.  On code like
   that in test/Sema/decl-invalid.c it causes us to return a single
   error instead of multiple.
2. Fix an error in Sema::ParseDeclarator, where it would crash if the
   declarator didn't have an identifier.  Instead, diagnose the problem.
3. Start adding infrastructure to track the range of locations covered
   by a declspec or declarator.  This is mostly implemented for declspec,
   but could be improved, it is missing for declarator.

Thanks to Neil for pointing out this crash.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@40482 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Preprocessor/macro_disable.c b/test/Preprocessor/macro_disable.c
new file mode 100644
index 0000000..33b856d
--- /dev/null
+++ b/test/Preprocessor/macro_disable.c
@@ -0,0 +1,13 @@
+// RUN: clang -E %s | grep 'a: 2 + M_0(3)(4)(5);' &&
+// RUN: clang -E %s | grep 'b: 4 + 4 + 3 + 2 + 1 + M_0(3)(2)(1);'
+
+#define M_0(x) M_ ## x 
+#define M_1(x) x + M_0(0) 
+#define M_2(x) x + M_1(1) 
+#define M_3(x) x + M_2(2) 
+#define M_4(x) x + M_3(3) 
+#define M_5(x) x + M_4(4) 
+
+a: M_0(1)(2)(3)(4)(5);
+b: M_0(5)(4)(3)(2)(1);
+