tests: verify the shell test scripts are syntactically valid Fixes automake bug#11898. This measure of extra safety is mostly motivated by the fact that some shells (at least some versions of Bash in the 3.x release series, one of which serves as /bin/sh on Mac OS X 10.7, as well as Bash 4.0 and the /usr/xpg4/bin/sh shell from Solaris 10) erroneously exit with exit status 0 upon encountering a syntax error, if an exit trap is sett (as it is in our test scripts). * Makefile.am (check-tests-syntax): New, check that the shell test scripts listed in $(TESTS) are syntactically correct. (.PHONY, check-local): Depend on it. * t/self-check-exit.tap : Remove checks verifying that a script exits with non-zero status upon encountering a syntax error; as explained above, we can't depend on that. Signed-off-by: Stefano Lattarini <stefano.lattarini@gmail.com>