in reply to Can plXPCOM be revived?
Concentrate on the "error" messages. Don't be too concerned with the "warning" messages (to begin with, at least).
To avoid the first "error" message that you see, try inserting "DEFINE => ' -DMOZILLA_INTERNAL_API'," into the WriteMakefile() section of the Makefile.PL ... and see how things pan out from there.
Cheers,
Rob