I see that <machine/lock.h> is being installed in /usr/include.  Are the
locking primitives kernel only or also useable by userland?  I was
considering changing the locking primitive to a compare-and-swap that
uses curproc as the identifier.  It's a great aid in debugging locking
issues but obviously wouldn't work in userland.  And I wouldn't want to
use a SPARC V9 instruction in 32-bit binaries.

Eduardo Horvath