Fix issues with WG14 N3344 changes

This amends 24e2e25 with a fix for
'register void *', which is still okay as a function parameter.

Author: AaronBallman

clang/lib/Sema/SemaDecl.cpp

@@ -15021,7 +15021,8 @@ Decl *Sema::ActOnParamDeclarator(Scope *S, Declarator &D,
                                             : diag::warn_deprecated_register)
           << FixItHint::CreateRemoval(DS.getStorageClassSpecLoc());
     } else if (!getLangOpts().CPlusPlus &&
-               DS.getTypeSpecType() == DeclSpec::TST_void) {
+               DS.getTypeSpecType() == DeclSpec::TST_void &&
+               D.getNumTypeObjects() == 0) {
       Diag(DS.getStorageClassSpecLoc(),
            diag::err_invalid_storage_class_in_func_decl)
           << FixItHint::CreateRemoval(DS.getStorageClassSpecLoc());

clang/test/C/C2y/n3344.c

@@ -16,6 +16,7 @@
 void baz(volatile void);         // expected-error {{'void' as parameter must not have type qualifiers}}
 void bar(const void);            // expected-error {{'void' as parameter must not have type qualifiers}}
 void foo(register void);         // expected-error {{invalid storage class specifier in function declarator}}
+void foop(void register);        // expected-error {{invalid storage class specifier in function declarator}}
 void quux(static void);          // expected-error {{invalid storage class specifier in function declarator}}
 void quobble(auto void);         // expected-error {{invalid storage class specifier in function declarator}}
 void quubble(extern void);       // expected-error {{invalid storage class specifier in function declarator}}
@@ -28,3 +29,7 @@ void quabble(_Thread_local void); // expected-error {{'_Thread_local' is only al
 #endif
 void bing(void, ...);            // expected-error {{'void' must be the first and only parameter if specified}}
 
+// These declarations are fine.
+void one(register void *);
+void two(void register *);
+void three(register void * (*)[4]);