Make hookset<T> a pointer type, just like purehookset.

No more declaring `hookset<T> *hooks_foo`; now it's just
`hookset<T> hooks_foo` at global scope. This clears the way to
make `hookset<T>` into a class type if we want.

hyper-main.cpp

@@ -29,7 +29,7 @@ void moreStack() {
 #endif
 
 namespace hr {
-EX hookset<bool(int argc, char** argv)> *hooks_main;
+EX hookset<bool(int argc, char** argv)> hooks_main;
 
 EX int hyper_main(int argc, char **argv) {
   using namespace hr;