IPATH sets the path to the header (.h) files, ie. /usr/include
LPATH sets the path to the library (.so/.a) files, ie. /usr/lib64 or /usr/lib
LIBS sets the names of the actual libraries to use (with .so/.a and the ‘lib’ prefix stripped), eg. “ssl crypto”
If you’re looking to simply compile Panda from source, I would advise you to use makepanda instead, it automatically locates libraries on your system.