bin/43643: dash prefix broken with make -j

[dholland%eecs.harvard.edu@localhost]

>Number:         43643
>Category:       bin
>Synopsis:       dash prefix broken with make -j
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Jul 19 23:40:01 +0000 2010
>Originator:     David A. Holland
>Release:        NetBSD 5.99.30 (20100610), also 20100719, and also in -4
>Organization:
>Environment:
System: NetBSD macaran 5.99.30 NetBSD 5.99.30 (MACARAN) #2: Thu Jun 10 23:29:26 
EDT 2010  
root%macaran.eecs.harvard.edu@localhost:/usr/src/sys/arch/amd64/compile/MACARAN 
amd64
Architecture: x86_64
Machine: amd64
>Description:

Make recipe lines can be prefixed with '-' to prevent stopping on
error. This stops working when -j is enabled.

>How-To-Repeat:

Use this makefile:

   ------
foo:
        -false
   ------

and do

% make
% make -j1

>Fix:

Dunno, will look into it if I get a chance.

Note that the .IGNORE attribute, which is supposed to be the same as
the dash prefix, still works in -j mode, so it's not as much the same
as it's advertised to be. It also seems to have a minor cosmetic bug:

   % make
   false
   *** Error code 1 (ignored)
   % make -j1
   false
   *** [foo] Error code 1(ignored)
   % 
                        ^^

which rather suggests it's using a different code path. (sigh)