Add 'make check' as a synomym for 'make test'.

This is what they call it where I come from.
Merge pull request #2 from rillian/fixes

add `make check` as alias for `make test`

That's the GNU way, people seem to care and it's not intrusive, so why not.
https://www.gnu.org/prep/standards/standards.html#Standard-Targets
be consistant with target ordering. check is before test, so reflect that in .PHONY
Add 'dist' and 'distcheck' make targets.

Creates a tarball with a version name derived from git.

This is a traditional autotools feature for automating release
packaging, replicated here in custom make. The dist target is
ad hoc but works for the source configurations currently in tree.

Also corrects a missing build dependency on missing.h.
Use install in the dist target body.

This simplifies the shell code considerably, at the expense
of removing the executable bit from scripts.