So it seems you've tried a lot of things, and that is confusing the issue. As far I can see, none of the things in this line are going to work:
https://github.com/PR2/linux_networki...
It appears there is a copy of wpa_supplicant in both the wpa_supplicant package and the wpa_supplicant_node package. I'm not sure which one you want to do, but is there a reason you don't just install wpa_supplicant from apt-get?
This is one of the root issues, from where do you want to get utils/list.h?
If utils/list.h is to be provided from wpa_supplicant_node, then you just need something like this in the CMakeLists.txt of wpa_supplicant_node:
include_directories(wpa_supplicant/src)
Because in that case utils/list.h is in <git root>/wpa_supplicant_node/wpa_supplicant/src/utils/list.h. You were close, you had this in the above linked line: ${catkin_INCLUDE_DIRS}wpa_supplicant/src, but the missing space between ${catkin_INCLUDE_DIRS} and wpa_supplicant/src causes them to be concatenated, so that will not work. I think if you put a space between those two and remove all the other entries it should work.
If utils/list.h is provided by another package (like wpa_supplicant) then you'll need to do something like what is suggested here:
http://answers.ros.org/question/93266...
Basically you need to install the header add the folder which contains utils/list.h to your exported include paths for the wpa_supplicant package.
If wpa_supplicant is to be used from the system (installed using apt-get) then your pkg-config approach in wpa_supplicant_node, which is currently commented out, might work. You'd have to look at wpa_supplicant's upstream documentation to find out how you are supposed to build against it.
