diff --git a/pkgs/development/libraries/gperftools/default.nix b/pkgs/development/libraries/gperftools/default.nix
index 47c6134dd201..e6d1fd3b6403 100644
--- a/pkgs/development/libraries/gperftools/default.nix
+++ b/pkgs/development/libraries/gperftools/default.nix
@@ -16,6 +16,8 @@ stdenv.mkDerivation rec {
     substituteInPlace libtool --replace stdc++ c++
   '';
 
+  NIX_CFLAGS_COMPILE = stdenv.lib.optional stdenv.isDarwin "-D_XOPEN_SOURCE";
+
   # some packages want to link to the static tcmalloc_minimal
   # to drop the runtime dependency on gperftools
   dontDisableStatic = true;