Something like :
$export LD_LIBRARY_PATH=./lib
$ll ./lib
total 400
lrwxrwxrwx 1 stof stof 19 jui 15 20:20 libSDL-1.2.so.0 -> libSDL-1.2.so.0.0.5*
-rwxr-xr-x 1 stof stof 405239 jui 15 20:20 libSDL-1.2.so.0.0.5*
$tremulous
That way, tremulous will look for libSDL first in the ./lib folder, and then in the standard location. Be careful with relative paths though.
Edit : fucking stupid phpBB that stupidly closed for me the code tag. I hate dumb programs that act as if they are smart :evil: