unbreak world, take 2
authorJohn Marino <draco@marino.st>
Mon, 16 Feb 2015 14:38:24 +0000 (15:38 +0100)
committerJohn Marino <draco@marino.st>
Mon, 16 Feb 2015 14:38:24 +0000 (15:38 +0100)
commitf9931f0499c3e12bab6e371d21decb89d9e4df18
tree119cad77b123918696c68264250df2a377703238
parent2a66d7e272714700a8fcd4850a837f3c4ab9552d
unbreak world, take 2

The previous style works in the world makefiles but not here.
Try to fix the unbreak by checking if .MAKE.BUILT.BY is defined before
attempting to use it.
share/mk/sys.mk