Stop trying to remove packages in hidden directories, such as zfs snapshot dirs

Approved by:	marcus
Don't strip all spaces from env files, just the ones immediately following =

Approved by:	marcus
Touch a src.conf on makeJail

Since r248751, world build fails if SRCCONF is set to non-default value and
the file doesn't exist, to make troubleshooting easier.

http://lists.freebsd.org/pipermail/svn-src-head/2013-March/046032.html

Approved by:	marcus
Fix build error mails.

The code formerly checked for getBuildCompletionUsers
rather than getBuildErrorUsers, and failed when the
logs didn't have a suffix

Approved by:	marcus
Add .MAKE.LEVEL to exclusion list of variables to unset

bmake exports .MAKE.LEVEL as an envar, which breaks sh when it is attempted to
be unset.  This behaviour is apparently desirable according to upstream (sjg)

Approved by:	marcus
Only remove the first '.' in the jail name.
Revert the way distfiles are cached to that it continues to work with NFS.

Submitted by:	kuriyama
Sync with latest docs.
Currently clang 3.3 is intermittently failing to build pnohang, which results
in a hung state (processes are all killed, but the build is still locked).

Until the cause is found and fixed, use gcc where available.

Approved by:	marcus
Update to 4.0.1.
Fix fetch on IPv6 only hosts. PORTBUILD_USE_IPV6 ends up
being set blank instead of YES so it keeps being disabled.

Submitted by:	Bernhard Froehlich <decke@FreeBSD.org>
Approved by:	marcus
Add support for protocol flag in createJail command when using
LFTP update method.

Submitted by:	Bernhard Froehlich <decke@FreeBSD.org>
Approved by:	marcus
Fix some clang compiler issues.

Submitted by:	Marco BrÃder <marco.broeder@gmx.eu>
Fix a typo and some style issues.

Submitted by:	Marco BrÃder <marco.broeder@gmx.eu>
Attempt to fix enterbuild so that the sleepme file can be properly deleted.

Reported by:	Dave Hayes <dave@jetcafe.org>
Use the host's dialog4ports when setting OPTIONS.

Note: This means TB now needs to depend on dialog4ports.

Reported by:	David Nelson <david.nelson@gpsdo.com>