Extra "installation hierarchy" for private libraries?

[Warwick Harvey]

Hi,

One thing I do reasonably often is build my own private library modules, for 
use in a number of different programs in different directories.  On beddoe, 
where I maintain my own Mercury installation, I can just install these in 
the main directory hierarchy.  However, when I work on other machines (i.e. 
the UniMelb machines) this option is not really available to me (nor would I 
want it to be for such a public installation).  Specifying alternate 
locations for finding interface files and libraries currently seems 
moderately cumbersome (one must specify appropriate -I, -L and -R flags).  
This is particularly true if one wishes to be able to conveniently work with 
multiple grades or multiple architectures, since the directories specified 
using -L and -R must be different for each combination.

It seems to me that the solution to this is to provide some support in the 
Mercury scripts so that one can specify an alternative "installation 
hierarchy" (or, more generally, a list thereof) which would be searched in 
the same way as and in addition to the main installation hierarchy.  
Ideally, one would just set a single flag in the Mmakefile, and everything 
would work, regardless of grade or architecture (assuming one had installed 
that particular combination :-).

Does this seem like a good idea / the right way to go about it?

Comments welcome...

Warwick