Building the MSI hook on Windows
(`contrib/win-installer/podman-msihooks/check.c`)
currently requires MinGW. This commit updates the build
script so that, when MinGW is absent but the C compiler
included in Visual Studio BuildTools is installed, the
latter is used to build the MSI hook.
Other than that, `winmake.ps1` has a new `installertest`
target to run the Windows installer tests that are
currently verified by Cirrus CI.
Signed-off-by: Mario Loriedo <mario.loriedo@gmail.com>
Mario Loriedo