I'm setting this specific bug as wontfix. reprotest, to the extent
possible while still testing reproducibility, tries to simulate the
environment that it's called in, so that calling reprotest with a build
command is similar to calling the build command without reprotest.
Changing specific environment variable values is up to the build tools, the
source itself, or the one building the software. I'll ask the mailing list
if it's better to set $HOME to an existing or nonexisting directory.
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