Support for GCC 7 and 8 can continue on an as-needed basis. The
goal is not to explicitly break support for such compilers. Chances
are they will continue to compile Catch2 for some time into the
future. Rather, it no longer seems a prudent use of resources to
continuously test with these compilers.
The old `Start-FileDownload` was no longer recognized by the pswh
version on my local machine, this updates the OpenCppCoverage install
script to use a still usable cmdlet.
We still want to build VS 2017 through AppVeyor, and those images
have CMake 3.16.2 installed. We could install newer CMake as part
of the build, but since we don't use newer CMake features yet, this
is simpler.
`gmtime*` on Windows fails on dates pre 1970, and because we didn't
check the return code, we would then pass invalid `tm` struct to
`strftime` causing it to assert.
Closes#2944
Turns out that even in GCC, the expression in `__builtin_cosntant_p`
can end up evaluated and side-effects executed. To allow users to
work around this bug, I added a configuration option to disable its
use in internal macros.
Related to #2925
While isatty() is a POSIX interface and theoretically could be used
more broadly than on Linux and macOS, use a conservative approach and
use it on any platform that uses GNU libc.
In case the warning -Werror=conversion is active with GCC, the warnings
about "conversion from A to B may change value" lead to a compilation
error. This explicitly convert the values to address these warnings.
