Make process title - % complete

[Ivan Voras]

I have a small patch that makes "make" display percentage complete in 
process title, which can be retrieved in "top" in the form of:

71466 root             1  76    0  7008K  5696K select  0   0:00  0.00% 
make: 95% (55 more targets out of 1360) (make)

The patch is here and I'm inviting reviews and suggestions:

http://people.freebsd.org/~ivoras/diffs/make.c.patch

if nobody objects, I'll commit it :)