headers in sub-subdirectories, and gnustep-make 2.2.1

[Nicola Pero]

I implemented having headers in sub-subdirectories.

For example, consider a framework called Beauty.  Let's you have headers

 Beauty_HEADER_FILES = Beauty.h Vanity.h

then your headers would be in

  Beauty/Beauty.h
  Beauty/Vanity.h

and end up installed as in

 Beauty.framework/Beauty/Beauty.h
 Beauty.framework/Beauty/Vanity.h

and you include them as in

  #import <Beauty/Beauty.h>
  #import <Beauty/Vanity.h>


Now the new feature is that you can specify headers that live in  
subdirectories, as in

 Beauty_HEADER_FILES = Beauty.h Vanity.h Pride/Pride.h

(note the last one, Pride/Pride.h) then your headers would be in

  Beauty/Beauty.h
  Beauty/Vanity.h
  Beauty/Pride/Pride.h

and end up installed as in

 Beauty.framework/Headers/Beauty.h
 Beauty.framework/Headers/Vanity.h
 Beauty.framework/Headers/Pride/Pride.h

(note: the last header requires creating a directory, which is now  
automatically created for you)
and you include them as in

  #import <Beauty/Beauty.h>
  #import <Beauty/Vanity.h>
  #import <Beauty/Pride/Pride.h>

---

As soon as this change has been tested, I'd like to release gnustep- 
make trunk as gnustep-make 2.2.1.

I guess we could wait a week or two, then we could release. :-)

I have other changes I'd like to make, but it's worth shipping the  
current batch of changes to end-users first. :-)

Thanks