rapidcheck: Use stock installation, multiple outputs

We had neglected to nice `RC_INSTALL_ALL_EXTRAS`, which will take care
of installing the "extras" for us.

Now that they are in a standard directory, we don't need to smuggle in
the extra `-I` for Nix's tests either.

pkgs/development/libraries/rapidcheck/default.nix

@@ -16,20 +16,15 @@ stdenv.mkDerivation rec {
     hash = "sha256-nq2VBDREkAOnvtdYr3m0TYNXx7mv9hbV5HZFVL2uTTg=";
   };
 
+  outputs = [ "out" "dev" ];
+
   nativeBuildInputs = [ cmake ];
 
   cmakeFlags = [
     (lib.cmakeBool "BUILD_SHARED_LIBS" (!stdenv.hostPlatform.isStatic))
+    (lib.cmakeBool "RC_INSTALL_ALL_EXTRAS" true)
   ];
 
-  # Install the extras headers
-  postInstall = ''
-    cp -r $src/extras $out
-    chmod -R +w $out/extras
-    rm $out/extras/CMakeLists.txt
-    rm $out/extras/**/CMakeLists.txt
-  '';
-
   passthru.updateScript = unstableGitUpdater { };
 
   meta = with lib; {

pkgs/tools/package-management/nix/common.nix

@@ -182,8 +182,6 @@ self = stdenv.mkDerivation {
     "--enable-gc"
   ] ++ lib.optionals (!enableDocumentation) [
     "--disable-doc-gen"
-  ] ++ lib.optionals atLeast214 [
-    "CXXFLAGS=-I${lib.getDev rapidcheck}/extras/gtest/include"
   ] ++ lib.optionals stdenv.isLinux [
     "--with-sandbox-shell=${busybox-sandbox-shell}/bin/busybox"
   ] ++ lib.optionals (atLeast210 && stdenv.isLinux && stdenv.hostPlatform.isStatic) [