Allow BusyBox to be invoked as "<something>-busybox". This is
necessary when it's run from the Nix store as <hash>-busybox during
stdenv bootstrap.
--- busybox-1.25.1-orig/libbb/appletlib.orig	2016-10-26 19:54:20.510957575 -0400
+++ busybox-1.25.1/libbb/appletlib.c	2016-10-26 19:48:31.590862853 -0400
@@ -884,7 +884,7 @@
 	int applet;
 
 # if ENABLE_BUSYBOX
-	if (is_prefixed_with(name, "busybox"))
+	if (strstr(name, "busybox") != 0)
 		exit(busybox_main(argv));
 # endif
 	/* find_applet_by_name() search is more expensive, so goes second */