Erik:
Some recent build failures reminded me of this issue and increased the
need to fix it ASAP to be able to diagnose them. GenerateLinkOptData.gmk
runs a java tool to generate data which is later used to optimize the
JDK image with jlink. The problem here is that the tool needs to print
some of that data on stdout, which the build captures as one build
artifact, and will print some "garbage" on stderr if things go well. So
currently we just hide all that output from the build log. Because of
this, if something goes wrong, we won't see the error.
This patch tries to capture the stderr output and only print it (along
with stdout) if the java command fails.
Bug: https://bugs.openjdk.java.net/browse/JDK-8204564
Webrev: http://cr.openjdk.java.net/~erikj/8204564/webrev.01/
Looks good.
Tim
