Request for review: Defs-util.gmk missing in new build system, preventing build

[Magnus Ihse Bursie]

Background: Building with the new build system fails with 
".../common/shared/Defs-utils.gmk: No such file or directory" in the 
build forest, but not in the build-infra forest.

It turned out that a file got missing (!) when we did the integration 
from the build-infra forest to the build forest. Defs-utils.gmk was an 
empty file, which nevertheless was included by another makefile 
(Defs.gmk). Both of these files are part of the copy of the old make 
system, which we continuosly remove as we convert more and more to the 
new build system. In this case, the contents of Defs-utils.gmk had been 
removed, but not the reference to it. The proper cause of action would 
of course have been to delete the file and the reference. Since both 
files are to be deleted soon anyway, it didn't seem to matter.

... apart from the fact that the webrev patch don't contain new, empty, 
files. So Defs-util.gmk got lost when the patch from the build-infra 
forest was applied on build forest, even though it was listed on the 
webrev index.html page... In my view, this is a bug in the webrev 
script, that probably should be looked at.

There are two ways to solve this problem: either we properly create the 
Defs-utils.gmk file in the build forest as well, or we remove the 
reference to it. The former will just correct the part missing from the 
original patch (but that was part of the code reviewed webrev of M1) but 
seems a bit silly. The latter feels better but is, actually, a real change.

I created two webrevs for the two solutions:

http://cr.openjdk.java.net/~ihse/defs-util-missing/restore-empty-file.webrev.00/

and

http://cr.openjdk.java.net/~ihse/defs-util-missing/remove-reference.webrev.00/

In any case, I hope we can get this fixed soon since people are starting 
to test the new build system now that it's more widely available, and 
I'm getting lots of identical bug reports on this one. :-)

/Magnus