gtest: build shared library

Arch provides shared library as well.

pkgs/development/libraries/gtest/default.nix

@@ -3,6 +3,8 @@ stdenv.mkDerivation rec {
   name = "gtest-${version}";
   version = "1.8.1";
 
+  outputs = [ "out" "dev" ];
+
   src = fetchFromGitHub {
     owner = "google";
     repo = "googletest";
@@ -12,6 +14,10 @@ stdenv.mkDerivation rec {
 
   nativeBuildInputs = [ cmake ninja ];
 
+  cmakeFlags = [
+    "-DBUILD_SHARED_LIBS=ON"
+  ];
+
   meta = with stdenv.lib; {
     description = "Google's framework for writing C++ tests";
     homepage = https://github.com/google/googletest;