Trying to figure out some umask issues

[Jason L Tibbitts III]

I do a large number of local mock builds as a part of the package
reviews that I do, and one problem I consistently run into is
executables and .so files coming out with mode 775, but a scratch
build in Fedora's koji instance showing the expected 755 permissions.

I thought it might be some local environment leaking into my mock
builds, but my personal umask is 022 which should be OK and changing
it doesn't alter the result anyway.

Init'ing a fresh chroot shows the default umask in it is 0002, which
would seem to explain things but wouldn't explain why the Fedora
buildsys has different results.  Is there customization done there to
force the umask somehow?

 - J<