czmq: Fix build on Glibc 2.24

http://hydra.nixos.org/build/38982107

pkgs/development/libraries/czmq/default.nix

···
 { stdenv, fetchurl, zeromq }:
 
 stdenv.mkDerivation rec {
-  baseName="czmq";
-  version="3.0.2";
-  name="${baseName}-${version}";
+  version = "3.0.2";
+  name = "czmq-${version}";
 
   src = fetchurl {
     url = "http://download.zeromq.org/${name}.tar.gz";
     sha256 = "16k9awrhdsymx7dnmvqcnkaq8lz8x8zppy6sh7ls8prpd6mkkjlb";
   };
+
+  # Fix build on Glibc 2.24.
+  NIX_CFLAGS_COMPILE = "-Wno-error=deprecated-declarations";
 
   # Needs to be propagated for the .pc file to work
   propagatedBuildInputs = [ zeromq ];