reptyr: fixup build with glibc-2.25

pkgs/os-specific/linux/reptyr/default.nix

@@ -7,6 +7,12 @@ stdenv.mkDerivation rec {
     url = "https://github.com/nelhage/reptyr/archive/reptyr-${version}.tar.gz";
     sha256 = "07pfl0rkgm8m3f3jy8r9l2yvnhf8lgllpsk3mh57mhzdxq8fagf7";
   };
+
+  # Avoid a glibc >= 2.25 deprecation warning that gets fatal via -Werror.
+  postPatch = ''
+    sed 1i'#include <sys/sysmacros.h>' -i platform/linux/linux.c
+  '';
+
   makeFlags = ["PREFIX=$(out)"];
   meta = {
     platforms = stdenv.lib.platforms.linux;