[src/trunk]: src/usr.bin/make Document what I wrote for PR/40115

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/1409af1e2d67
branches:  trunk
changeset: 764791:1409af1e2d67
user:      christos <christos%NetBSD.org@localhost>
date:      Wed May 04 21:14:56 2011 +0000

description:
Document what I wrote for PR/40115

diffstat:

 usr.bin/make/make.1 |  24 +++++++++++++++++++++++-
 1 files changed, 23 insertions(+), 1 deletions(-)

diffs (45 lines):

diff -r 3e5a5fab4864 -r 1409af1e2d67 usr.bin/make/make.1
--- a/usr.bin/make/make.1       Wed May 04 20:38:31 2011 +0000
+++ b/usr.bin/make/make.1       Wed May 04 21:14:56 2011 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: make.1,v 1.189 2011/05/04 20:38:32 sjg Exp $
+.\"    $NetBSD: make.1,v 1.190 2011/05/04 21:14:56 christos Exp $
 .\"
 .\" Copyright (c) 1990, 1993
 .\"    The Regents of the University of California.  All rights reserved.
@@ -2019,6 +2019,21 @@
 so that they still appear to be variable expansions.
 In particular this stops them being treated as syntax, and removes some
 obscure problems using them in .if statements.
+.Pp
+Unlike other
+.Nm
+programs, this implementation by default executes all commands for a given
+target using a single shell invocation.
+This is done for both efficiency and to simplify error handling in remote
+command invocations.
+Typically this is transparent to the user, unless the target commands change
+the current working directory using
+.Dq cd
+or
+.Dq chdir .
+To be compatible with Makefiles that do this, one can use
+.Fl B
+to disable this behavior.
 .Sh SEE ALSO
 .Xr mkdep 1
 .Sh HISTORY
@@ -2026,6 +2041,13 @@
 .Nm
 command appeared in
 .At v7 .
+This
+.Nm
+implementation is based on Adam De Boor's pmake program which was written
+for Sprint at Berkeley.
+It was designed to be a parallel distributed make running jobs on different
+machines using a daemon called 
+.Dq customs .
 .Sh BUGS
 The
 .Nm