gnu-tar: install as gtar, link gnubin/tar -> gtar

dpkg needs gnu-tar to install with a well-known name, so we mimic the
setup used by coreutils of always installing with the 'g' prefix, and
offering the clashing executable name in $opt/libexec/gnubin.

Signed-Off-By: Drew Fisher <zarvox@zarvox.org>

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
dpkg: use homebrew gtar and OSX md5, shasum

- The formula claims to depend on homebrew's gnu-tar package, but then
  uses OSX's bundled gnutar, rather than homebrew's gnutar.  On older
  OSX machines, this breaks, as dpkg 1.17 depends on tar >= 1.23, see
  http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=642802

- dpkg-scanpackages fails, since md5sum, sha1sum, and sha256sum don't
  exist.  So replace the invocations with OSX's md5 and shasum tools.

Signed-Off-By: Drew Fisher <zarvox@zarvox.org>

Closes #22019.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
assenger: fix apache config module path caveats.

Closes #22513.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
gpsbabel: remove expat, used for docs.

Expat is included on OSX. All that is needed by gpsbabel beyond the system expat is the xmlwf command to build the docs. Tried to make the docs build work but even with expat and docbook dependencies they don't seem to build.
gpsbabel: improve argument handling.
Stop mutating dependency specifications
head DSL can accept a block
Move SoftwareSpec to a separate file
Teach SoftwareSpec about dependencies
Track initialized specs
Track dependencies in SoftwareSpec
wip
wip