Fix regression in handling VAR=VALUE arguments to testsuite.
* lib/autotest/general.m4 (AT_INIT) <PARSE_ARGS_END>: Detect
leading = as invalid. Defer use of command-line variable
assignments...
<PREPARE_TESTS>: ...here, after atconfig has been sourced. Fix
regression in sourcing files.
* tests/autotest.at (Using atlocal): New test to catch this.
(Debugging a successful test, Choosing where testsuite is run):
Use correct shell.
Reported by Ralf Wildenhues.