Copy files with qmake to ouput directory from an external directory?

I use this in my .pro files to copy files to the build output directory: DESTDIR = ../bin__output__ assets.path = $$DESTDIR/assets assets.files += $$files(assets/*.*)   INSTALLS += assets Now I want to copy files that are located in “/usr/lib…” into the build ouput directory. Of course I want to copy them only if they do not already exist or if they have been modified in the build output directory. And I want to do this on Linux (and then on Windows). I checked a few suggestions but none of them worked like these here [stackoverflow.com].