* main.c (main): Sanitize program name detection on Windows.
* makeint.h: 'program' is a const string on all platforms now.
* tests/run_make_tests.bat: Windows bat file to invoke tests
* tests/test_driver.pl: Obtain system-specific error messages.
(get_osname): Compute the $port_type here.  Add more $osname checks
for different Windows Perl ports.
(_run_command): Rewrite the timeout capability to work properly
with Windows.  Don't use Perl fork/exec; instead use system(1,...)
which allows a more reliable/proper kill operation.
Also, allow options to be given as a list instead of a string, to
allow more complex quoting of command-line arguments.
* tests/run_make_tests.pl (run_make_with_options): Allow options
to be provided as a list in addition to a simple string.
(set_more_defaults): Write sample makefiles and run make on them
instead of trying to run echo and invoking make with -f-, to avoid
relying on shell and echo to get basic configuration values.  Also
create a $sh_name variable instead of hard-coding /bin/sh.
* tests/scripts/features/archives: Skip on Windows.
* tests/scripts/features/escape: Use list method for passing options.
* tests/scripts/features/include: Use system-specific error messages.
* tests/scripts/features/output-sync: "Command not found" errors
generate very different / odd output on Windows.  This needs to be
addressed but for now disable these tests on Windows.
* tests/scripts/functions/abspath: Disable on Windows.
* tests/scripts/functions/file: Use system-specific error messages.
* tests/scripts/functions/shell: "Command not found" errors generate
very different / odd output on Windows.  This needs to be addressed
but for now disable these tests on Windows.
* tests/scripts/misc/close_stdout: Disable on Windows.
* tests/scripts/options/dash-k: Use system-specific error messages.
* tests/scripts/options/dash-l: Disable on Windows.
* tests/scripts/options/eval: Use list method for passing options.
* tests/scripts/options/general: Skip some non-portable tests.
* tests/scripts/targets/ONESHELL: Skip some non-portable tests.
* tests/scripts/targets/POSIX: Skip some non-portable tests.
* tests/scripts/variables/MAKEFILES: Skip some non-portable tests.
* tests/scripts/variables/SHELL: Use a makefile not -f- for testing.