gnustep-make optimized

[Nicola Pero]

Hi 

I studied the performance of the gnustep-make package tonight, and was
able to improve the performance pretty dramatically.  The new
gnustep-make - pretty quicker than the old one - is on CVS.  I left
out all minor optimizations for now, and worked only on the two major
ones.

Here are some examples on my system <all times are averages over 10
repetitions of the same thing>

`make install' in the base library: 

 it took on average: 13.193 seconds
 after optimizations o.a. it takes: 5.3251 seconds (40.3% of the original time)

`make' in the base library when everything is already compiled (so
that all the time is purely spent by the make system):

 it took on average: 8.6319 seconds
 after optimizations o.a. it takes: 2.8410 seconds (32.9% of the original time)

`make' in the gui library when everything is already compiled:

 it took: 3.6745 seconds
 it takes: 1.6910 seconds (46% of the original time)

`make' in the examples when everything is already compiled:

 it took: 13.0299 seconds
 it takes: 8.0520 seconds (61.8% of the original time)

As you see, the more complicated the source tree is, the more the
optimizations are effective.