You’ll need to modify these files:
$DTOOL/Config.pp
$DTOOL/LocalSetup.pp
$DTOOL/Package.pp
$DTOOL/pptempl/Global.pp
$PANDA/src/pandabase/pandasymbols.h
Plus whatever files you need to add in $PANDA/src/
I learned this the hard way when I was making awesomium work with panda.