More GCC compatibility/warning fixes (#3118)

* Wrap >4-char literals in a MULTI_CHAR macro

Modern compilers do not support CW's non-standard behavior with
>4 char literals. We can, however, use a constexpr function to
compute the u64 values directly. This leaves <=4 char literals
unchanged.

* Replace non-pointer usages of NULL with 0

* Define NULL to nullptr on C++11 and above

* Fix more -Wpointer-arith and -Woverflow warnings

* Replace u32/s32 with uintptr_t/intptr_t where appropriate

* JSUOutputStream: Overload all standard int types

src/d/actor/d_a_npc_tkj2.cpp

@@ -176,7 +176,7 @@ static void Wind_effect(npc_tkj2_class* i_this) {
                     if ((s16)(sVar1 - i_this->field_0x5c4) < 0) {
                         cLib_addCalcAngleS(&a_this->shape_angle.z, 0x2000, 0x10, 0x1000, 0);
                     } else {
-                        cLib_addCalcAngleS(&a_this->shape_angle.z, 0xFFFFE000, 2, 0x1000, 0);
+                        cLib_addCalcAngleS(&a_this->shape_angle.z, -8192, 2, 0x1000, 0);
                     }
                 }