There are two ways to pass configuration variables to ./configure
, and it depends quite a bit on the specific project, so you have to check the documentation.
The first one is to use the --with...
options that the author of the script have decided to provide. For example, xcircuit
has to be configured like this in 14.04:
./configure --with-tcl --with-tk --with-tcllibs=/usr/lib/x86_64-linux-gnu/ --with-tklibs=/usr/lib/x86_64-linux-gnu/
The other way is passing an environment variable to the script (in configuration stage) or to the Makefile (in the compilation phase):
CPPFLAGS=-Wall ./configure
or
CPPLAGS=-Wall make
In summary, it's really up to how the author wrote the software. You should refer to the specific documentation, in you case, of libav.