Adding path using configure.in.in

[Pascal Francq]

Hi,
I have the following problem:
- I use a shared library 'rstd'.
- I have a program that is based on this library 'myapp'.

The shared library is developed on my computer. So I want to make my program 
compile using the include files and the library in '/home/pfrancq/rstd/rstd'. 
Other people that use the program have the library installed in '/usr/lib' 
and the include files in '/usr/include/rstd'.
I know that it is possible to make some magick in configure.in.in of 'myapp' 
to make it looks first on directory specify by an environment variable 
RSTD_LIB, and if not found in the normal directories ('/usr/lib', 
'/usr/include/rstd', '/usr/local/lib','/usr/local/include/rstd').
But, I do not know how to do. Anyone an example that I can use?
-- 


Dr Ir Pascal Francq
Researcher
Université Libre de Bruxelles
CAD/CAM Department
Avenue F.D. Roosevelt, 50
CP 165/14
B-1050 Brussels
BELGIUM
Tel. +32-2-650 47 65
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