diff --git a/release.nix b/release.nix
index b20435f8..dd28cef0 100644
--- a/release.nix
+++ b/release.nix
@@ -1,5 +1,5 @@
 { hydraSrc ? builtins.fetchGit ./.
-, nixpkgs ? builtins.fetchGit { url = https://github.com/NixOS/nixpkgs-channels.git; ref = "nixos-18.09-small"; }
+, nixpkgs ? builtins.fetchGit { url = https://github.com/NixOS/nixpkgs-channels.git; ref = "nixos-19.03-small"; }
 , officialRelease ? false
 , shell ? false
 }:
@@ -137,6 +137,10 @@ rec {
 
       preConfigure = "autoreconf -vfi";
 
+      NIX_LDFLAGS = [
+          "-lpthread"
+	];
+
       enableParallelBuilding = true;
 
       preCheck = ''