[TreeProcMT] Move static functions to anonymous namespace
[TreeProcMT] Move static functions to anonymous namespace

...to make it clear that we only use these functions in this same
source file.

karies/root,karies/root,karies/root,olifre/root,karies/root,olifre/root,olifre/root,karies/root,olifre/root,root-mirror/root,root-mirror/root,olifre/root,root-mirror/root,olifre/root,root-mirror/root,olifre/root,karies/root,root-mirror/root,olifre/root,olifre/root,root-mirror/root,karies/root,karies/root,karies/root,root-mirror/root,root-mirror/root,root-mirror/root,root-mirror/root,root-mirror/root,olifre/root,karies/root,olifre/root,karies/root