Document "build.sh cleandir".

Fix formatting nit.
Remove BUGS; all the in-tree platforms are using build.sh now.

BUILDING

@@ -622,6 +622,8 @@ BUILDING
      makewrapper   Create the nbmake-MACHINE wrapper.  This operation is auto-
                    matically performed for any of the other operations.
 
+     cleandir      Perform ``make cleandir''.
+
      obj           Perform ``make obj''.
 
      tools         Build and install the host tools from src/tools.  This com-
@@ -864,7 +866,4 @@ HISTORY
      The build.sh based build scheme was introduced for NetBSD 1.6 as
      USE_NEW_TOOLCHAIN, and re-worked to TOOLCHAIN_MISSING after that.
 
-BUGS
-     A few platforms are not yet using this build system.
-
-NetBSD                          August 11, 2008                         NetBSD
+NetBSD                          August 18, 2008                         NetBSD

doc/BUILDING.mdoc

@@ -1,4 +1,4 @@
-.\"	$NetBSD: BUILDING.mdoc,v 1.62 2008/08/11 08:22:40 apb Exp $
+.\"	$NetBSD: BUILDING.mdoc,v 1.63 2008/08/18 05:27:05 lukem Exp $
 .\"
 .\" Copyright (c) 2001-2008 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -33,7 +33,7 @@
 .\" Toolchain prefix for commands
 .ds toolprefix nb
 .
-.Dd August 11, 2008
+.Dd August 18, 2008
 .Dt BUILDING 8
 .Os NetBSD
 .
@@ -1028,7 +1028,7 @@ utility, which is not part of
 but which can be installed from
 .Pa pkgsrc/sysutils/cdrtools .
 .
-.It iso-image-source
+.It Sy iso-image-source
 Create a
 .Nx
 installation CD-ROM image in the
@@ -1161,6 +1161,10 @@ wrapper.
 This operation is automatically performed for any of the other
 operations.
 .
+.It Sy cleandir
+Perform
+.Dq make cleandir .
+.
 .It Sy obj
 Perform
 .Dq make obj .
@@ -1698,7 +1702,3 @@ as
 and re-worked to
 .Sy TOOLCHAIN_MISSING
 after that.
-.
-.Sh BUGS
-.
-A few platforms are not yet using this build system.