build: fix pkg-config output parsing in configure
Fix parsing of pkg-config --cflags-only-I
. The configure_library()
step sometimes appended a list in a list instead of list of strings to
include_dirs.
This commit removes the default handling for includes and libpath options. They don't have defaults at the moment and I don't see that changing anytime soon. Fixing the code is more work and because it's dead code anyway, I opted to remove it instead.
Fixes: https://github.com/nodejs/io.js/issues/1985
CI: https://jenkins-iojs.nodesource.com/view/iojs/job/iojs+any-pr+multi/7/