[Qt-interest] Basic qmake question

[Phil]

Thank you for reading this.

I'm attempting to create an application with Qtcreator that uses the 
qextserialport library.

I have compiled qextserialport and saved a link to the generated library 
file (libqextserialport.so.1.0.0) in /usr/lib/. My application .pro file 
includes the line  "LIBS    += -lqextserialport".

My application compiles correctly except for this error:
"/usr/bin/ld: cannot find -lqextserialport".

I've fiddled with this for most of the afternoon to get this far and I feel 
that I must be close to the answer, but not quite. Can anyone offer a 
suggestion?

-- 
Regards,
Phil