diff --git a/pkgs/applications/science/biology/bcftools/default.nix b/pkgs/applications/science/biology/bcftools/default.nix
index 71ceca12224..7ae62b15d34 100644
--- a/pkgs/applications/science/biology/bcftools/default.nix
+++ b/pkgs/applications/science/biology/bcftools/default.nix
@@ -14,7 +14,7 @@ stdenv.mkDerivation rec {
 
   makeFlags = [
     "HSTDIR=${htslib}"
-    "prefix=$out"
+    "prefix=$(out)"
     "CC=cc"
   ];