share install should build a more minimal cmake3

[plicease]

Recent versions of cmake have a "server" mode which, with a dependency on libuv, and probably other stuff as well. None of this is useful for Alien::cmake3 so it would be nice for a share source install to disable theses features, to save time building and probably exe bloat.

this adds the ability do disable server mode from using the autoconf style bootstrap script:
https://gitlab.kitware.com/cmake/cmake/commit/ec0bf63823ff459d742a54fae4c8582b5b87d1dd
(which is what we use since we don't have cmake yet) but it doesn't seem to be in the current version.

Here is some commentary on disabling it when building without bootstrap:
https://cmake.org/pipermail/cmake/2016-November/064565.html
(which is not how we build, but maybe we can adapt this).

[plicease]

Looks like server mode has been deprecated and may be removed in the future. Problem solved?