Fix Uniscribe build

If a pointer type was passed to Null(), reinterpret_cast<> was
complaining about qualifiers being removed. Turns out I need the const on
the other side of "Type" to fix that.  Also remove unused const from
NullPool type.

src/dump-emoji.cc

@@ -47,7 +47,7 @@
 #include <stdio.h>
 
 #ifndef HB_NO_VISIBILITY
-const void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
+void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
 thread_local void * _hb_CrapPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
 #endif
 

src/dump-fon.cc

@@ -27,7 +27,7 @@
 #include "hb-open-type-private.hh"
 
 #ifndef HB_NO_VISIBILITY
-const void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
+void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
 thread_local void * _hb_CrapPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
 #endif
 

src/hb-ot-layout.cc

@@ -47,7 +47,7 @@
 
 
 #ifndef HB_NO_VISIBILITY
-const void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
+void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
 thread_local void * _hb_CrapPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
 #endif
 

src/hb-private.hh

@@ -550,16 +550,16 @@ static
 #else
 extern HB_INTERNAL
 #endif
-const void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)]
+void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)]
 #ifdef HB_NO_VISIBILITY
 = {}
 #endif
 ;
 /* Generic nul-content Null objects. */
 template <typename Type>
-static inline const Type& Null (void) {
+static inline Type const & Null (void) {
   static_assert (sizeof (Type) <= HB_NULL_POOL_SIZE, "Increase HB_NULL_POOL_SIZE.");
-  return *reinterpret_cast<const Type *> (_hb_NullPool);
+  return *reinterpret_cast<Type const *> (_hb_NullPool);
 }
 #define Null(Type) Null<Type>()
 

src/hb-subset.cc

@@ -45,7 +45,7 @@
 
 
 #if !defined(HB_NO_VISIBILITY) && !defined(HB_SUBSET_BUILTIN)
-const void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
+void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
 thread_local void * _hb_CrapPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
 #endif
 

src/main.cc

@@ -38,7 +38,7 @@
 using namespace OT;
 
 #ifndef HB_NO_VISIBILITY
-const void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
+void * const _hb_NullPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
 thread_local void * _hb_CrapPool[HB_NULL_POOL_SIZE / sizeof (void *)] = {};
 #endif