tree 1c626dc747029820179e2f73debb4d8cf7ae2283
parent 0894cbc1a9f0564e77dfbe74ed09d03bc7eaf30d
author Dan Willemsen <dwillemsen@google.com> 1437432937 -0700
committer Dan Willemsen <dwillemsen@google.com> 1437439881 -0700

Don't print module header if nothing is defined

Modules may decide not to output any build definitions in some cases.
Clean up the ninja file by not adding headers for empty sections.

One particular usecase is my upcoming multi-stage bootstrapping -
bootstrap_go_* will not output any rules in the first stage unless it's
required to build the primary builder.

Change-Id: I6a6b54da7e1702c63bfa736bcf8daf16956f9449