We've been having some build issues with pkgsrc recently. One of the main issues has been libarchive which moved to a new extattr ABI. Snapshots have been broken for too long because of this and other issues.
The only way to solve this properly is to update our extattr ABI (basically dummy system calls in our case). I have done this on HEAD and MFCd the work into the 2.6 branch. Once we get daily snapshot builds and pkgsrc bulk builds working again I intend to do another mini-release cycle for 2.6. The next mini-release will probably occur in 1.5 to 2 weeks. -Matt