Add "dist" and "distcheck" targets to CMake

[dbaston]

From Bas Couwenberg:

autotools and cmake take the opposite approach to creating distribution archives.

autotools only includes the files it is configured to.

cmake includes everything in the source tree not explicitly excluded.

To support make dist with CMake you need to add a custom target:

add_custom_target(dist COMMAND ${CMAKE_MAKE_PROGRAM} package_source)

And configure CPACK_SOURCE_IGNORE_FILES to exclude everything that should not end up in the archives.

For make distcheck you'll need to implement more custom targets.

NetCDF may be a source of inspiration:

​https://github.com/Unidata/netcdf-c/blob/master/cmake/modules/FindMakeDist.cmake

[strk]

I think "include all by default" is a dangerous approach, and hard to check, and hard to produce an "uninstall" rule for either (we do want "uninstall" too!)

[dbaston]

Resolved by pramsey in git:44acf18e52a6ed

[Paul Ramsey <pramsey@…>]

In 583ee56/git:

Remove undefined behaviour in use of null PrecisionModel, closes #931

[Paul Ramsey <pramsey@…>]

In efda6148/git:

Remove undefined behaviour in use of null PrecisionModel, closes #931

[Paul Ramsey <pramsey@…>]

In bd3e599/git:

Remove undefined behaviour in use of null PrecisionModel, closes #931

[Paul Ramsey <pramsey@…>]

In e784aa1/git:

Remove undefined behaviour in use of null PrecisionModel, closes #931

[Paul Ramsey <pramsey@…>]

In e745ccb/git:

Remove undefined behaviour in use of null PrecisionModel, closes #931

[Paul Ramsey <pramsey@…>]

In 3b02d4a/git:

Remove undefined behaviour in use of null PrecisionModel, closes #931