libargon2: do not override pre/postInstall hook

pkgs/development/libraries/libargon2/default.nix

@@ -3,6 +3,7 @@
 stdenv.mkDerivation rec {
   name = "libargon2-${version}";
   version = "20161029";
+
   src = fetchFromGitHub {
     owner = "P-H-C";
     repo = "phc-winner-argon2";
@@ -11,14 +12,16 @@ stdenv.mkDerivation rec {
   };
 
   installPhase = ''
-    mkdir -p $out
-    make install PREFIX=$out
+    runHook preInstall
     mkdir -p $out/lib/pkgconfig
     substitute libargon2.pc $out/lib/pkgconfig/libargon2.pc \
       --replace @UPSTREAM_VER@ "${version}"                 \
       --replace @HOST_MULTIARCH@ ""                         \
       --replace 'prefix=/usr' "prefix=$out"
+
+    make install PREFIX=$out
     ln -s $out/lib/libargon2.so $out/lib/libargon2.so.0
+    runHook postInstall
   '';
 
   meta = with stdenv.lib; {