RE: CI: windows

[Jannick]

Hi Akim,

looking into travis a bit, here something which might be easier (locally I
am working along the following lines as well):
- use the MSYS2 shell
(https://docs.travis-ci.com/user/reference/windows/#how-do-i-use-msys2), my
favorite unix-like shell on windows. bison, flex, m4, perl etc. are shipped
in its base package.  Applying the script in the aforementioned link makes
sure that they are all found on PATH of each of the shells MSYS2, MINGW32
and MINGW64. The following assumes using the MING64 shell.
- For doxygen say 'pacman -S doxygen'.
- For msvc compilation I usually use clang64 (install with, e.g., 'pacboy
clang:x') which usually looks for the installed MSVC compiler on the system.
- Using clang and ./configure in the MINGW64 shell: clang's triplet is not
well understood by config.sub, so some tweaks are needed to charm
./configure and its friends. ;)  Note that a shell-specific config.site
setting defaults is called by ./configure for each of the shells MSYS2,
MINGW32 and MINGW64.

Appveyor (https://www.appveyor.com/docs/build-environment) might be an
alternative to consider which apparently is widely used.

HTH.
J.