[Insight-developers] Preventing Out Of Source Builds -- http://review.source.kitware.com/#change, 157

[kent williams]

This came up on the 16th, and I was out until yesterday. I just spent 45
minutes catching up on ITK Developer list e-mail.

First off -- I hate in-source builds in general.  They're so 1987.  I can't
think of a single reason to do them with ITK.  That being said, I don't
personally care whether someone wants to do one.

Therefore I just pushed a small change that adds a option named
ALLOW_IN_SOURCE_BUILDS

The scenario at configure time -- for the fan of in-source builds:

1. Configure in-source. CMake complains loudly about it.
2. In the Cache (and visible in the GUI) there is now
    ALLOW_IN_SOURCE_BUILDS:BOOL=OFF
3. User toggles that option, and now he or she can go on their merry way
    with an in-source build.

There's another issue I don't really understand, which is there are 4 files
that get modified by an in-source build that are actually tracked by git:

#    modified:   Utilities/gdcm/Copyright.txt
#    modified:   Utilities/nifti/Makefile
#    modified:   Utilities/nifti/niftilib/Makefile
#    modified:   Utilities/nifti/znzlib/Makefile

A die hard in-source build guy might check those in by accident. It wouldn't
matter that much since I think those Makefiles are ignored by CMake in favor
of using the CMakeLists.txt file.

But as far as I'm concerned those could be removed from the ITK repository.
ITK does track those external packages, but any merging is done manually and
carefully.  Having them in ITK just confuses the issue.