dirmngr: add a mirror.

The current mirror seems to be dead. I've given it about 36 hours but
no sign of revival yet. Just in case, this merge adds the debian
package mirror.

Closes #30642.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
mercurial 3.0.2
mercurial: update 3.0.2 bottle.

Closes #30644.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
lilypond devel 2.19.9

Closes #30651.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
fix ghc --tests option
fix --devel on os x 10.9.3 using clang wrapper
fix path problems
os x lion can't use clang
ghc: update 7.6.3_2 bottle.