No C89 compatible toolchain does "pure C89" without extra options (if at all); people would run away. Even if you use GCC or CLANG with the -std=c89 option it doesn't. So the complaints that the presented library is not "pure C89" is nothing but an academic quibble.
EDIT: I now have changed the repository description to "A pure C (-std=c89) implementation of Go channels, including blocking and non-blocking selects.", so hopefully this idiotic discussion will come to an end.
EDIT: I now have changed the repository description to "A pure C (-std=c89) implementation of Go channels, including blocking and non-blocking selects.", so hopefully this idiotic discussion will come to an end.