mdoc(7) police: macroize UNIX.

share/man/man9/DEVICE_PROBE.9

@@ -50,7 +50,9 @@ For
 cases where more than one driver matches a device, a priority value can
 be returned.  In this case, success codes are values less than or equal
 to zero with the highest value representing the best match.  Failure
-codes are represented by positive values and the regular Unix error
+codes are represented by positive values and the regular
+.Ux
+error
 codes should be used for the purpose.
 .Pp
 If a driver returns a success code which is less than zero, it must

share/man/man9/sleep.9

@@ -129,7 +129,8 @@ See above.
 .Xr mi_switch 9
 .Sh HISTORY
 The sleep/wakeup process synchronization mechanism is very old.  It
-appeared in a very early version of Unix.
+appeared in a very early version of
+.Ux .
 .Pp
 .Nm Tsleep
 appeared in

share/man/man9/spl.9

@@ -189,7 +189,8 @@ raised the interrupt priority to its own level, i.e. further interrupts
 of the same group are being blocked.
 .Sh HISTORY
 The interrupt priority levels appeared in a very early version of
-Unix.  They have been traditionally known by number instead of by
+.Ux .
+They have been traditionally known by number instead of by
 names, and were inclusive up to higher priority levels (i.e., priority
 5 has been blocking everything up to level 5).  This is no longer the
 case in

share/man/man9/vnode.9

@@ -146,7 +146,9 @@ struct vnode {
 
 .Ed
 .Sh DESCRIPTION
-The vnode is the focus of all file activity in UNIX.  There is a
+The vnode is the focus of all file activity in
+.Ux .
+There is a
 unique vnode allocated for each active file, each current directory,
 each mounted-on file, text file, and the root.
 .Pp