Fix some more GCC warnings, mark some bugs based on GCC warnings (#2309)

* Fix some more GCC warnings, mark some bugs based on GCC warnings

* Weird formatting

* Suggested changes

* More weird indentation I guess

* UNREACHABLE() macro, add missing NORETURNs to fault_n64.c

* AVOID_UB for PAL path in z_file_nameset.c

* Remove comments about return types

* Remove temp no longer needed

src/code/sys_cfb.c

@@ -8,7 +8,7 @@ uintptr_t sSysCfbEnd;
 
 void SysCfb_Init(s32 n64dd) {
     u32 screenSize;
-    uintptr_t tmpFbEnd;
+    UNUSED_NDEBUG uintptr_t tmpFbEnd;
 
     if (osMemSize >= 0x800000) {
         PRINTF(T("８Ｍバイト以上のメモリが搭載されています\n", "8MB or more memory is installed\n"));