[Groff] Cygwin and pre-html failures, there is a bug

[Alejandro Lopez-Valencia]

I think I have figured out the problem with cygwin. pre-html is not calling 
gs properly. The argument line is chopped off:

 1948 5141775 [main] pre-grohtml 1184 spawn_guts: 1532 = spawn_guts 
(/usr/bin/sh, d:\cygwin\bin\sh.exe -c "echo showpage | gs.exe -q -dBATCH 
-dSAFER -dDEVICEHEIGHTPOINTS=792 -dDEVICEWIDTHPOINTS=700 -dFIXEDMEDIA=tru)

It fails and there is a retry, which fails as well:

 1360   56060 [main] sh 1368 spawn_guts: 1368 = spawn_guts 
(/usr/local/bin/gs.exe, d:\cygwin\usr\local\stow\gs\bin\gs.exe -q -dBATCH 
-dSAFER -dDEVICEHEIGHTPOINTS=792 -dDEVICEWIDTHPOINTS=700 -dFIXEDMEDIA=true 
-sDEVIC)

Thus, the resulting pnm file is empty, or non existent. This is a bug in 
Cygwin's runtime :(.

On the other hand, I think the proper work-around would be to invoke gs and 
the netpbm utilities with command lines set externally in the DESC file or 
somewhere else instead of a hard-wired command option. Same for the netpbm 
utilities. I, for one, would rather use ImageMagick or GraphicMagick if 
given the option.