Re: [ITA] cmake 3.12.0

[Ivan Shynkarenka <chronoxor@gmail.com>]

 > One of the main reasons I haven't put in the effort to update the cmake
> package is that recent versions of cmake have new dependencies which it
> vendors by default, which is not the way distros such as cygwin prefer to
> build things. For a cygwin packaging build of cmake (as with other tools),
> the "right way" is presumably to use system versions of all library
> dependencies.

Cmake 3.12.0 builds successfully out of box for Cygwin with default build
script provided by Kitware.
So I think its a good chance to build and update the package. Moreover I
tested it in lots of our C++
projects that must be build under Cygwin via Appveyor CI. For this reason I
add pre-build step with
building the latest cmake:

  - if "%type%"=="Cygwin" appveyor-retry appveyor DownloadFile "
https://cmake.org/files/v3.12/cmake-3.12.0.tar.gz" -FileName "cmake.tar.gz"
  - if "%type%"=="Cygwin" C:\cygwin64\bin\bash -lc "cd
$APPVEYOR_BUILD_FOLDER; mkdir temp; cd temp; mv ../cmake.tar.gz
./cmake.tar.gz; tar xzf cmake.tar.gz --strip-components=1; ./bootstrap &&
make && make install; cd ..; rm -rf ./temp"

Of course the best solution for us is to have cmake 3.12.0 updated in
Cygwin repository, because its building time is about ~30min