Related changes:
* BoostBuild.Tester & TestCmd.TestCmd interfaces now accept external process parameters as a list of strings, thus avoiding problems with parsing arguments containing spaces.
* Avoided a potential process hang in case an external process being run prints out enough output to fill up the OS's pipe buffer (OS would pause the process until someone read the data from the pipe but the testing framework would not do this until the process in question had terminated).
[SVN r79448]
are communiated via return value of 'abstract-target.generate', not as
attribute of virtual target. The advantage is that we can return usage
requirements, even if no targets were created.
Also, usage requirements is not really attribute of virtual target. If several
virtual targets are created for one main target, the previous code would set
the same usage requirements on all virtual targets.
[SVN r18689]
* new/targets.jam
(basic-target.generate-source): Separate virtual targets that come from
different sources.
(basic-target.check-for-unused-targets): Warn only if not virtual target
from a given source is comsumed.
[SVN r18403]
* new/targets.jam
(basic-target.check-for-unused-sources): New rule.
(basic-target.generate): Call the above.
* new/virtual-target.jam
(traverse): New arguments 'include-roots' and 'include-sources'.
* test/unused.py: New test.
[SVN r17685]
