abuild rootbld: disable real chown calls in fakeroot
By default, fakeroot forwards chown system calls to the libc and ignores
EPERM errors. Unfortunately, when fakeroot is used inside a restricted
bubblewrap environment (as created by
abuild rootbld), bubblewrap intercepts these system calls and
EINVAL return value is not masked by fakeroot and
returned to the caller, thereby causing failures of
install(1), … which
use chown system calls internally.
FAKEROOTDONTTRYCHOWN environment variable prevents the chown
systemcalls to be performed in the first place.
Fixes #10021 (closed)