FreeBSD: exclude some includes when building libsa

[mmatuska]

Motivation and Context

The function abd_alloc_from_pages() is not used in FreeBSD base libsa.
Excluding sys/vm.h, and vm/vm_page.h includes avoids dependency problems.

Description

Exclude abd_alloc_from_pages(), sys/vm.h, and vm/vm_page.h when building libsa.

How Has This Been Tested?

FreeBSD base build

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the OpenZFS code style requirements.
• I have updated the documentation accordingly.
• I have read the contributing document.
• I have added tests to cover my changes.
• I have run the ZFS Test Suite with this change applied.
• All commit messages are properly formatted and contain Signed-off-by.

[amotin]

I wonder if #ifdef _KERNEL would be more appropriate. That is how I see the function calls are wrapped.

[behlendorf]

Using #ifdef _KERNEL would be more consistent with how this is handled elsewhere in ZFS. @mmatuska unless there are good reasons not to switch this could you please update the PR.

[mmatuska]

Using #ifdef _KERNEL would be more consistent with how this is handled elsewhere in ZFS. @mmatuska unless there are good reasons not to switch this could you please update the PR.

Thank you for the hint, PR updated.