[MacPorts] #54752: cmake 1.1 PG : ccache support

[MacPorts]

#54752: cmake 1.1 PG : ccache support
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  Reporter:  RJVB         |      Owner:  (none)
      Type:  enhancement  |     Status:  new
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:
Resolution:               |   Keywords:
      Port:               |
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Comment (by RJVB):

 Replying to [comment:8 kencu]:
 > It is in the cmake 1.1 PG <https://github.com/macports/macports-
 ports/blob/722e1970778c525e7b85ceb2cdb3a83fc1a9cf31/_resources/port1.0/group/cmake-1.1.tcl#L193>.
 >
 > but do you actually see it working?

 Hah, I did have a recollection about going through the motions to get this
 in, I should have checked.

 Yes, this works for me. There are projects that roll their own
 implementation in their CMake files which may then interfere with what the
 PG does. Projects designed to use a central, precompiled headerfile also
 tend to gain nothing from using ccache. Using LTO will cut your possible
 gain roughly in half. Barring those there is no reason why it wouldn't
 work. @kencu: do you have an example where it doesn't?

 Of course you won't see much benefit with one-time builds. I also have the
 impression that ccache won't use the cached code from the same file built
 in a different (source) directory. The interest is mostly for port
 maintainers who may rebuild a port many times with minimal changes that
 would invalidate the ccache caches. Then the gain can be enormous.

-- 
Ticket URL: <https://trac.macports.org/ticket/54752#comment:10>
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