profile: append manpath for default profile

[LnL7]

No description provided.

[domenkozar]

See #229, we should only set it if it already exists

[LnL7]

This should fix any issues with duplicates

[edolstra]

This still doesn't check whether $MANPATH is already set. We don't want to mess with $MANPATH if it's unset, because that screws up the default man search path (which is derived from $PATH).

[domenkozar]

Yes, we should check if $MANPATH has any value (instead of current implementation where it check if it already has the value we're expending it to)

[LnL7]

The issue with that approach is that $MANPATH probably won't be empty on other platforms, where this will be most useful. What about checking uname -a?

[domenkozar]

We should append only if it's already set.

[domenkozar]

Closing in favor of #1005