change pll_nitems from atomic -> int just to avoid races against pll_remove; add peeking and stack/queues support on item retrieval, although peeking should rarely be used due to inherent race conditions
change pll_nitems from atomic -> int just to avoid races against pll_remove; add peeking and stack/queues support on item retrieval, although peeking should rarely be used due to inherent race conditions

git-svn-id: f2acecaac6fbd5a03f3d4799db58dda434111981@4855 3eda493b-6a19-0410-b2e0-ec8ea4dd8fda

pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/pfl,pscedu/pfl,pscedu/pfl,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/slash2-stable,pscedu/pfl