Debian now has a few disadvantages:
-there is no convenient PPA for Debian tesseract 4.0, but there is for
Ubuntu
-Ubuntu sets locale to UTF-8 automatically removing the need to do this
All three ocrmypdf docker images are now based on a common Ubuntu
16.10 image, derived from the one used to build ocrmypdf-tess4.
-polyglot now differs from -tess4 only by opting into the tess4 PPA.
Both Ubuntu 16.10 and Debian stretch use tesseract 3.04.01 now making
the sharp.ttf patch unnecessary. /etc/apt/sources has been unused for a
while now both have newer Ghostscripts.
James R. Barlow