imagemagick: make --without-magick-plus-plus optional

Closes #19254.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>
john: enable OpenCL and OpenMP support for --jumbo

Closes #19105.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
Add :hg build requirement.

Closes #19074.
Reorder dep spec types by frequency
Merge remote-tracking branch 'upstream/master'