security/qca2-qt5-ossl and ninja

[Greg Troxel <gdt%lexort.com@localhost>]

With

   CMAKE_GENERATOR?=               ninja

in mk.conf, qca2-qt5-ossl fails to build.  Cleary it just doesn't work
with ninja.

There's a user-settable variable that I set, and there are no
package-settable variables to say that make is the only allowed
GENERATOR.


I am guessing that:

  I should set CMAKE_GENERATOR=make.

  I should amend the docs in cmake/build.mk to say this is the approach
  for now, because there is no CMAKE_GENERATORS_ACCEPTED
  package-settable variable.


If that's wrong, please explain...