VMS exit status fixes.

[John E. Malmberg]

In checking the GNU make documentation, it states that error code 1 is 
for when make -q is used and the test fails.

As this is considered a failure status on Unix (non-zero), it should 
also be considered a failure status on VMS.

It best matched to a failure status of STS$K_WARNING, with the error 
code 2 be STS$K_ERROR as it is now.

The other logical alternative would be for severity for MAKE_TROUBLE to 
also to be STS$K_ERROR, which would force DCL scripts to actually look 
at the status code to determine the difference.

To have MAKE_TROUBLE be informational status would not be correct since 
it is documented to be a failure condition.

Regards,
-John