svn commit: r265097 - head

[Brooks Davis]

Author: brooks
Date: Tue Apr 29 16:57:25 2014
New Revision: 265097
URL: http://svnweb.freebsd.org/changeset/base/265097

Log:
  Merge from CheriBSD:
  
  commit 1d1b908107255ffdff4d17f015d8f057d73cc6cb
  Author: Brooks Davis <brooks at one-eyed-alien.net>
  Date:   Fri Mar 28 16:24:45 2014 +0000
  
      Add a long needed seatbelt.
  
      Exit with an error when make is called without a target at the top level
      rather than poluting the source tree and causing use confusion in future
      builds.
  
  commit a9d9aa341b2f4308a227ab460ba85f1f287ad028
  Author: Brooks Davis <brooks at one-eyed-alien.net>
  Date:   Tue Apr 29 16:06:12 2014 +0000
  
      Simplify seatbelt added in 1d1b908 based in feedback.
  
      Discussed with:	imp at FreeBSD.org
  
  Reviewed by:	imp
  Sponsored by:	DARPA, AFRL

Modified:
  head/Makefile

Modified: head/Makefile
==============================================================================
--- head/Makefile	Tue Apr 29 16:51:28 2014	(r265096)
+++ head/Makefile	Tue Apr 29 16:57:25 2014	(r265097)
@@ -238,8 +238,17 @@ tinderbox toolchains kernel-toolchains: 
 ${TGTS}:
 	${_+_}@cd ${.CURDIR}; ${_MAKE} ${.TARGET}
 
-# Set a reasonable default
-.MAIN:	all
+# The historic default "all" target creates files which may cause stale
+# or (in the cross build case) unlinkable results. Fail with an error
+# when no target is given. The users can explicitly specify "all"
+# if they want the historic behavior.
+.MAIN:	_guard
+
+_guard:
+	@echo
+	@echo "Explicit target required (use \"all\" for historic behavior)"
+	@echo
+	@false
 
 STARTTIME!= LC_ALL=C date
 CHECK_TIME!= find ${.CURDIR}/sys/sys/param.h -mtime -0s ; echo