dep/imgui: Don't copy the font data on building

For the CJK and SVG fonts, this is a **considerable** memory allocation
and copy, up to 20MB+. We really don't want to be doing this
unnecessarily, since we keep the buffer around anyway.

dep/imgui/src/imgui_draw.cpp

@@ -2504,12 +2504,15 @@ ImFont* ImFontAtlas::AddFont(const ImFontConfig* font_cfg)
     ImFontConfig& new_font_cfg = ConfigData.back();
     if (new_font_cfg.DstFont == NULL)
         new_font_cfg.DstFont = Fonts.back();
+#if 0
+    // DUCKSTATION-CHANGE: We maintain the allocations ourselves. Saves copying 14MB or so.
     if (!new_font_cfg.FontDataOwnedByAtlas)
     {
         new_font_cfg.FontData = IM_ALLOC(new_font_cfg.FontDataSize);
         new_font_cfg.FontDataOwnedByAtlas = true;
         memcpy(new_font_cfg.FontData, font_cfg->FontData, (size_t)new_font_cfg.FontDataSize);
     }
+#endif
 
     if (new_font_cfg.DstFont->EllipsisChar == (ImWchar)-1)
         new_font_cfg.DstFont->EllipsisChar = font_cfg->EllipsisChar;