Recursive make speedup patch

[Oliver Eikemeier]

Kris Kennaway wrote:

> The patch available at
> 
>   http://people.freebsd.org/~kris/recursive-speedup.patch
> 
> gives a 43% speedup for 'make index' in my testing:
> 
> No optimization
> 1899.40 real       648.67 user      1148.96 sys
> 
> Optimized version
> 1096.76 real       504.48 user       565.90 sys

Btw, great job!