the libz-rs-sys cdylib is not a drop-in replacement to libz

[glandium]

Build the cdylib:

$ cargo build -p libz-rs-sys

Download an example program using zlib in C:

$ wget https://www.zlib.net/zpipe.c

Compile and link against libz-rs-sys:

$ cc -o zpipe zpipe.c target/debug/deps/liblibz_rs_sys.so

(Funnily enough, because cargo doesn't set a SONAME on cdylib, this links the library such that running the resulting executable works without a LD_LIBRARY_PATH)

Run the program:

$ ./zpipe
zpipe: zlib version mismatch!