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_obj_lv6TogeRoll.cpp

@@ -206,7 +206,7 @@ void daTogeRoll_c::moveTogeRoll() {
             &daTogeRoll_c::modeBound, &daTogeRoll_c::modeBound2,   &daTogeRoll_c::modeBoundWait,
         };
 
-        if (field_0x5dc == NULL) {
+        if (field_0x5dc == 0) {
             for (int i = 0; i < 8; i++) {
                 if (mSph[i].ChkCoHit()) {
                     fopAc_ac_c* hit_actor = dCc_GetAc(mSph[i].GetCoHitObj()->GetAc());
@@ -264,7 +264,7 @@ void daTogeRoll_c::init_modeBoundWait() {
 }
 
 void daTogeRoll_c::modeBoundWait() {
-    if (field_0x5db != NULL) {
+    if (field_0x5db != 0) {
         field_0x5db -= 1;
     } else {
         field_0x5dc = 0;