Now that Raven Software has released the acc source code, I've taken it and bumped it up to version 1.11. If you are using ZETH, I strongly encourage you to use this new version. The version of acc released by Raven software worked poorly with ZETH (it caused the computer to reboot when run under Windows), and I was only able to circumvent the problem by replacing the PMODE/W stub used by acc with a huge DOS/4GW stub. Acc 1.11 was compiled with DJGPP, so there should be no problems when running it with ZETH. Just replace the copy of acc4gw.exe that came with ZETH with this acc.exe and edit your zeth.ini file to use it instead.
Even if you don't use ZETH, you might still want to get the new acc, because I added support for C-style for loops. There was space for them in the source code, but the code to make them work hadn't been written yet. If you do use any scripts with for loops, the code acc generates will still be 100% compatible with both Hexen and ZDoom 1.17b.
You can get acc 1.11 all by itself, with the ZDoom editing package, or with ZETH 4.02. (If you already have ZETH 4.01, you just need to get acc by itself. The only difference between ZETH 4.02 and ZETH 4.01 is that ZETH 4.02 comes with acc 1.11 and uses it as the default script compiler instead of acc4gw.)