Fix build with imgui disabled Newer dhewm3 embeds imgui. To avoid the embedded code copy this fix is needed. (porting to use the packaged imgui is something for after Trixie)
[PATCH] Fix setting z_off64_t in minizconf.h checking if Z_LARGE64 is defined doesn't make much sense because that is from from zlib which this helps replace.. so on non-windows we always ran into the #define z_off64_t z_off_t case which doesn't give us a 64bit offset on 32bit systems.. Should work better now.
