Build log reports goldin returned error code '0'
Trying to build a package that contains a .app and a post_install.sh script, results in goldin returned error code '0'

As goldin is something that looks like you have created, I can't tell what specifically it is for.
Is this an issue with how the package is being created, the contents of the package, or something else?
Which version of Packages and what type of filesystem (HFS+, APFS, etc.)?
goldin is the tool that is used to split the Data Fork and Resources Fork if needed.
There's also potentially more information about the issue in the system.log file.
You can also try this build which should provide more information about the error. https://drive.google.com/open?id=0B_2n1wyuWXGVQ3RHU3VfLXZUQTQ
Not sure what happened, but a few days later (with no updates to the package or anything else) the error just disappeared. So not sure what went wrong there. I would say leave the issue open for others if they experience a similar problem maybe?
But to answer your question, I am on an APFS filesystem, and the version of packages was 1.2.4 (I believe at the time I reported)
I am also getting this error. I added a Pre-Installation script, which failed the installation. Then I removed it, ran the Build again, and am now getting this error. The rest of my Package has not been changed. Maybe it will be gone tomorrow?
I'm using build 1.2.3 (Build 372)
There's potentially more info in system.log. The commit I made on the 10th of April should present a correct error number. Bu this is for version 1.2.4.