[Cmake] external packages

[Cross, Geoff (CRD)]

What are the currently feelings on external packages under unix, and how to set the
INCLUDE_DIRECTORIES and LINK_LIBRARIES?  Ideally, I want to do as little in the configure script as
possible, so I was wondering whether it might be an idea to have the installer edit some file in the
source root that would look something like

MESA=/some/path
GTK=
HAS_NETLIB= 0
   .
   .
   .

Therefore, instead of 

./configure --mesa-path=/some/path --without-gtk --with-netlib ...

the installer would just edit this file, and type

./configure



Geoff.