Linux 4.18 added support for SIGSYS info in signalfd. Add the new
fields to signalfd_siginfo.

While the kernel has support for these new fields now, no libc has
shipped a release with the new signalfd fields.

Bumps [ctest](https://github.com/alexcrichton/ctest) from 0.2.4 to 0.2.6.
- [Release notes](https://github.com/alexcrichton/ctest/releases)
- [Commits](https://github.com/alexcrichton/ctest/commits

)

Signed-off-by: dependabot[bot] <support@dependabot.com>

There are none of them in `libc` except for `__progname` on Android, but
that one cannot be tested because it's not present in any header files.

Looks like Travis has moved on from our old images, so we're forced to
update.

The mmap(2) flag indicate that the mapping is used as a stack.

https://man.openbsd.org/mmap.2#MAP_STACK
https://marc.info/?l=openbsd-tech&m=152035796722258&w=2

Was able to move some of them up one level so they are valid on more
platforms with less duplication