RPATH for unit tests

[James K. Lowden]

The topic of default search paths reminded me of an old problem I've
never solved to my satisfaction.  Perhaps there's a feature I don't
know about.  

FreeTDS is three things from an autoconf point of view:

1.  libraries, shared and static
2.  utilities linked to the libraries
3.  unit tests

The problems are:

1.  How to make sure the unit tests link to the build directory and not
the install directory?  After all, the point of running the unit tests
is to test the code just built, not the old version currently
installed.  

2.  How to *test* the utilties against the libraries in the build tree,
but run them normally linked to the install tree?  

I solve these myself with LD_LIBRARY_PATH in a script at runtime.  I
estimate that puts me among 0.01% of the user base.  

I guess what I think I want is a way to frob the RPATH for case
#1, and a way to set LD_LIBRARY_PATH in make.am for case #2.  Currently
both get their RPATH set based on defaults determined by the configure
script.  

Certainly I need  a way to set the RPATH of utilities, which will be
installed and need to refer to installed libraries, from unit tests,
which won't and don't.  

If you are curious, the configure.ac can be found here:
http://gitorious.org/freetds/freetds/blobs/master/configure.ac