Fix JUT_ASSERT and several other macros (#2711)

* Fix JUT_ASSERT to be a nested define

* Switch names that appear in asserts to be constants instead of defines

* Replace `0` in asserts with `NULL` or `FALSE`

* Fix fpclassify

* Fix ARRAY_SIZE

* Use G_CM3D_F_INF

* More fixes for fpclassify

* Remove FLOAT_LABEL

* Remove incorrect FLAG_ON macro

* Remove UNK_BSS macro

* Silence clangd unused header warning for PCH

src/d/actor/d_a_npc_cd.cpp

@@ -3,7 +3,7 @@
 // Translation Unit: a/npc/d_a_npc_cd
 //
 
-#include "d/dolzel.h"
+#include "d/dolzel.h" // IWYU pragma: keep
 
 #include "d/actor/d_a_npc_cd.h"
 #include "d/actor/d_a_player.h"
@@ -218,7 +218,7 @@ dCcD_SrcCyl const daNpcCd_c::m_cylDat = {
 int daNpcCd_c::NpcCreate(int param_1) {
     J3DModelData* a_mdlData_p = getNpcMdlDataP(param_1);
 
-    JUT_ASSERT(470, 0 != a_mdlData_p);
+    JUT_ASSERT(470, NULL != a_mdlData_p);
 
     mpMorf = new mDoExt_McaMorfSO(a_mdlData_p, NULL, NULL, NULL, -1, 1.0f, 0, -1, &mCreature,
                                   0x80000, 0x11000084);