This makes it easier to create a diverted store, i.e.
NIX_REMOTE="local?root=/tmp/root"
instead of
NIX_REMOTE="local?real=/tmp/root/nix/store&state=/tmp/root/nix/var/nix" NIX_LOG_DIR=/tmp/root/nix/var/log
* Dockerfile: add GNU tar native dependency
`builtins.fetchTarball` requires GNU tar to be available in the $PATH in
order to unpack the fetched tarball (there is a FIXME comment for this),
which Alpine does not ship by default (it ships BusyBox tar).
* Dockerfile: add GNU bash native dependency
`nix-shell` defaults to invoking `bash` from the $PATH for the subshell.
In theory this can be overriden with the NIX_BUILD_SHELL environment
variable, but this does not work properly. `nix-shell` generates and
passes a script (`$rcFile`) to be executed by the subshell which uses
bashisms (`source` and `shopt`). Additionally, in interactive mode,
`nix-shell` passes the `--rcfile` argument to the shell, which is
another bashism.
Because `bash` is thus de-facto required, add `bash` as a native package
dependency to make it available for `nix-shell`.
Currently, man has issues finding man pages for Nix-installed
application (also, `nix-env --help` doesn't work). The issue is caused
by custom `$MANPATH` set by my system. That makes man use it instead of
searching in default location.
Either of next lines workaround the issue:
```sh
unset MANPATH
export MANPATH=$HOME/.nix-profile/share/man:$MANPATH
```
This patch adds the later line to the `nix-profile.sh` if user has
`MANPATH` set. (Not clearing `MANPATH` as that would be disrespect of
user's preferences.)
As a side-effect, host's man might find man pages installed by Nix.
This fixes instantiation of pythonPackages.pytest that produces a
directory with less permissions during one of it's tests that leads to
a nix error like:
error: opening directory ‘/tmp/nix-build-python2.7-pytest-2.9.2.drv-0/pytest-of-user/pytest-0/testdir/test_cache_failure_warns0/.cache’: Permission denied
