Put on some factor 30+ bikeshed repellent and export the internal

Makefile.inc1 underscore targets with a big warning that they are
intentionally undocumented, subject to change without notice and
might poison your dog etc.  If you don't know what they are, then they
are not meant for you to use.

I've added these by hand to so many many trees that I've lost count.  I
find them rather useful.

1 files changed, 7 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index 132c1153b489..fccd360543c9 100644
--- a/Makefile
+++ b/Makefile
@@ -58,12 +58,18 @@
 # Define the user-driven targets. These are listed here in alphabetical
 # order, but that's not important.
 #
+# Targets that begin with underscore are internal targets intended for
+# developer convenience only.  They are intentionally not documented and
+# completely subject to change without notice.
+#
 TGTS=	all all-man buildkernel buildworld checkdpadd clean \
 	cleandepend cleandir depend distribute distributeworld everything \
 	hierarchy install installcheck installkernel installkernel.debug\
 	reinstallkernel reinstallkernel.debug installworld \
 	libraries lint maninstall \
-	obj objlink regress rerelease tags update
+	obj objlink regress rerelease tags update \
+	_worldtmp _legacy _bootstrap-tools _cleanobj _obj \
+	_build-tools _cross-tools _includes _libraries _depend
 
 BITGTS=	files includes
 BITGTS:=${BITGTS} ${BITGTS:S/^/build/} ${BITGTS:S/^/install/}