lol

libiio: allow build on systems without avahi

https://github.com/NixOS/nixpkgs/pull/181875 seems to have made this
package and its downstream dependencies no longer build on
avahi-less systems. Let's make it possible for them to build again.

+4 -2
+4 -2
pkgs/development/libraries/libiio/default.nix
··· 6 6 , libxml2 7 7 , python 8 8 , libusb1 9 - , avahi 9 + , avahiSupport ? true, avahi 10 10 , libaio 11 11 , runtimeShell 12 12 , lib ··· 43 43 python 44 44 libxml2 45 45 libusb1 46 - avahi 47 46 ] ++ lib.optional python.isPy3k python.pkgs.setuptools 47 + ++ lib.optional avahiSupport avahi 48 48 ++ lib.optional stdenv.isLinux libaio 49 49 ++ lib.optionals stdenv.isDarwin [ CFNetwork CoreServices ]; 50 50 ··· 55 55 # the linux-like directory structure is used for proper output splitting 56 56 "-DOSX_PACKAGE=off" 57 57 "-DOSX_FRAMEWORK=off" 58 + ] ++ lib.optionals (!avahiSupport) [ 59 + "-DHAVE_DNS_SD=OFF" 58 60 ]; 59 61 60 62 postPatch = ''