Re: System includes

[Wayne Scott]

Some notes in response to your email.

* I mentioning /usr/include just because that is normally searched by
  GCC and is not by cons.  Some people might not know that.

* There are times when you do want a dependency on the system headers.
  For example if I am building a Linux module and I am getting the
  kernel headers from /usr/include/linux, I probably want to notice
  when the headers are changed.  Or when building on NFS on multiple
  machines and you want to recompile if your used the wrong headers.
  (A stretch I know...)

* Cons does not use signature stuff for files that are not within the
  project. (Or at least it didn't used to)  It can't assume it can
  write a .consign file outside your source tree, so only the file
  timestamp is used.

But yes for most people it doesn't really matter if the system files
are ignored in signature calculation.  They probably don't change.

-Wayne