add pkgconfig script
add pkgconfig script

kbranigan/libkdtree,kbranigan/libkdtree,nvmd/libkdtree,eddyxu/kdtree-serialization,nvmd/libkdtree,eddyxu/kdtree-serialization,nvmd/libkdtree,kbranigan/libkdtree,eddyxu/kdtree-serialization