Internal compiler error when decompiling certain tilesets

[grunt-lucas]

Describe the bug
Trying to decompile the compiled version of SmokingArmy's combined tileset gives:

porytiles: internal compiler error: array::at
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This is a bug. Please file an issue here:
https://github.com/grunt-lucas/porytiles/issues

In the issue body, please include the following info:
  - the above error message
  - the full command line you ran
  - any relevant input files
  - the version / commit of Porytiles you are using
  - the compiler (and settings) you built with (if you built from source)

Including these items makes it more likely a maintainer will be able to
reproduce the issue and create a fix release.

Note: I had to set the primary tiles override to 1024. I think this may have something to do with the bug. Will need to run it thru the debugger to see why the array access issue occurs.

Additional context

porytiles decompile-primary -Wall -o foo smoking_army_porytiles metatile_behaviors.h 

Original compilation command:

porytiles compile-primary -Wall -o foo -tiles-output-pal=true-color -tiles-primary-override=1024 smoking_army ./metatile_behaviors.h

Environment (please complete the following information):

• Used commit 1af1364 but bug probably occurs with all versions