Fix AppVeyor

[fingolfin]

Let's see if this fixes AppVeyor builds (w/o breaking coverage and what not else)

[fingolfin]

That did not help. Now it just dies in the next line:

SET "PATH=%CYG_ROOT%\bin;%PATH%"
bash -lc "python -m pip install gcovr"
Command exited with code 127

Perhaps the path is wrong now, or something else in that vein?

[codecov]

Codecov Report

Merging #3377 into master will decrease coverage by 15.91%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           master    #3377       +/-   ##
===========================================
- Coverage   85.13%   69.22%   -15.92%     
===========================================
  Files         697      633       -64     
  Lines      344069   305935    -38134     
===========================================
- Hits       292939   211769    -81170     
- Misses      51130    94166    +43036

Impacted Files	Coverage Δ
src/pperm.h	0% <0%> (-90.33%)	⬇️
src/tietze.c	1.11% <0%> (-88.99%)	⬇️
src/syntaxtree.c	11.47% <0%> (-88.53%)	⬇️
src/trans.h	0% <0%> (-85.72%)	⬇️
lib/ctblauto.gi	5.98% <0%> (-83.31%)	⬇️
src/vec8bit.c	1% <0%> (-81.63%)	⬇️
src/compiler.c	8.06% <0%> (-80.53%)	⬇️
lib/ctbllatt.gi	4.94% <0%> (-79.62%)	⬇️
src/dteval.c	3.1% <0%> (-78.24%)	⬇️
src/bits_intern.h	0% <0%> (-77.42%)	⬇️
... and 391 more

[fingolfin]

At least part of the problem is that there are two different Python's installed, one by cygwin and one by AppVeyor, and they mix in a bad way...

[wilfwilson]

AppVeyor works again!

[coveralls]

Coverage increased (+0.0006%) to 85.138% when pulling d835c6d on fingolfin:mh/appveyor into 9e7e38d on gap-system:master.