phpExtensions.iconv: fix build on Darwin after the SDK update (#348181)

          name = "iconv";

          buildInputs = [ libiconv ];

          configureFlags = [ "--with-iconv" ];

          # Some other extensions support separate libdirs, but iconv does not. This causes problems with detecting

          # Darwin’s libiconv because it has separate outputs. Adding `-liconv` works around the issue.

          env = lib.optionalAttrs stdenv.hostPlatform.isDarwin { NIX_LDFLAGS = "-liconv"; };

          doCheck = stdenv.hostPlatform.isLinux;

        }

        {