K 10
svn:author
V 3
phk
K 8
svn:date
V 27
2005-03-08T10:40:48.000000Z
K 7
svn:log
V 426
Reengineer subr_unit

	Add support for passing in a mutex.  If NULL is passed a global
	subr_unit mutex is used.

	Add alloc_unrl() which expects the mutex to be held.

	Allocating a unit will never sleep as it does not need to allocate
	memory.

	Cut possible range in half so we can use -1 to mean "out of number".

	Collapse first and last runs into the head by means of counters.
	This saves memory in the common case(s).

END