README: disambiguate what to distribute source of
README: disambiguate what to distribute source of

Indicate that if you make changes to libgit2 that you must distribute
the source _to libgit2_, not the source _of your program_.

Corillian/libgit2,Corillian/libgit2,stewid/libgit2,Corillian/libgit2,stewid/libgit2,stewid/libgit2,stewid/libgit2,Corillian/libgit2,stewid/libgit2,Corillian/libgit2,stewid/libgit2,Corillian/libgit2