Build fails with Ubuntu / gcc 9.3.0

[sstiller]

After running make release, I get the following compile errors:

Building release object Release/2d/assets/ParticleAssetFieldCollection.cc.o
gcc -c -std=gnu++11 -MMD -I. -Wfatal-errors -Wunused -m32 -msse -march=i686 -pipe -I/usr/include -I/usr/include/freetype2 -I../../source -I../../source/persistence/rapidjson/include -I../../lib/ljpeg -I../../lib/zlib -I../../lib/lpng -I../../lib/freetype -I../../lib/libvorbis/include -I../../lib/libogg/include -DLINUX -O0 ../../source/2d/assets/ParticleAssetFieldCollection.cc -o Release/2d/assets/ParticleAssetFieldCollection.cc.o
../../source/2d/assets/ImageAsset.cc: In member function ‘S32 ImageAsset::getExplicitCellIndex(const char*)’:
../../source/2d/assets/ImageAsset.cc:621:16: warning: converting to non-pointer type ‘int’ from NULL [-Wconversion-null]
  621 |         return NULL;
      |                ^~~~
../../source/2d/assets/ImageAsset.cc:647:12: warning: converting to non-pointer type ‘int’ from NULL [-Wconversion-null]
  647 |     return NULL;
      |            ^~~~

After replacing NULL by 0, I get:

make: *** No rule to make target 'Release/2d/assets/SkeletonAsset.cc.o', needed by '../../../Torque2D'.  Stop.

[greenfire27]

All torque engines have moved to a new organization, Torque Game Engines. Torque2D can be found at https://github.com/TorqueGameEngines/Torque2D. This repository will not be updated. We encourage you to use the new repository instead of this one. Thank you!

I'd also suggest you try the development branch of the other repository as that should definitely build on Ubuntu.