Log Message:
gnuradio*: USE_CMAKE exorcism

  - change to cmake/build.mk
  - set CMAKE_CONFIGURE_ARGS instead of CMAKE_ARGS
  - stop creating/using a build dir manually and don't override install
  - comment out the "don't use ninja" arm, since that happens
    naturally and the ninja option should be removed

Tested by building meta-pkgs/gnuradio on NetBSD 10.

ok @tnn