Rework the 'make -n -n' feature such that '-n' recurses and '-N' does not.

Bmake has a documented feature of '-N' to skip executing commands which is
specifically intended for debugging top-level builds and not recursing into
sub-directories.  This matches the older 'make -n' behavior we added which made
'-n -n' the recursing target and '-n' a non-recursing target.

Removing the '-n -n' feature allows the build to work as documented in
the bmake manpage with '-n' and '-N'.  The older '-n -n' feature was also
not documented anywhere that I could see.

Note that the ${_+_} var is still needed as currently bmake incorrectly
executes '+' commands when '-N' is specified.

The '-n' and '-n -n' features were broken for several reasons prior to this.
r251748 made '_+_' never expand with '-n -n' which resulted in many
sub-directories not being visited until fixed 2 years later in r288391, and
many targets were given .MAKE over the past few years which resulted in
non-sub-make commands, such as rm and ln and mtree, to be executed.

This should also allow removing some indirection hacks in bsd.subdir.mk and
other cases of .USE that have a .MAKE by using '+'.

Sponsored by:	EMC / Isilon Storage Division
Discussed on:	arch@ (mostly silence)

1 files changed, 6 insertions, 0 deletions

diff --git a/UPDATING b/UPDATING
index baff1f1..1095ba6 100644
--- a/UPDATING
+++ b/UPDATING
@@ -31,6 +31,12 @@ NOTE TO PEOPLE WHO THINK THAT FreeBSD 11.x IS SLOW:
 	disable the most expensive debugging functionality run
 	"ln -s 'abort:false,junk:false' /etc/malloc.conf".)
 
+20151017:
+	The build previously allowed using 'make -n' to not recurse into
+	sub-directories while showing what commands would be executed, and
+	'make -n -n' to recursively show commands.  Now 'make -n' will recurse
+	and 'make -N' will not.
+
 20151012:
 	If you specify SENDMAIL_MC or SENDMAIL_CF in make.conf, mergemaster
 	and etcupdate will now use this file. A custom sendmail.cf is now