Implement PRECIOUS builtin.

Note that existing code already tried to assume that the 'together'
flag means precious, but as described at:
http://public.perforce.com:8080/@md=d&cd=//public/jam/src/&cdf=//public/jam/src/make1.c&c=klD@/1494?ac=10
this was not really wrong.

Now, PRECIOUS makes the target never removed. I plan to extend it so that
user can control what exit codes cause the target to be removed.


[SVN r60157]
This commit is contained in:
Vladimir Prus 2010-03-04 23:02:57 +00:00
parent 16d3d4f5c9
commit b598f33d69

@ -1 +1 @@
Subproject commit 5f9ec5037816c6d6213686c1a0ecdf16eb6dc9ae
Subproject commit 52c1c81918c23da3007db0ff8fa39c9e95cd69af