Log Message:
emacs26-nox11: force-disable ns to fix build on MacOS

emacs26-nox11 is missing a fix made to emacs25, which disables ns
(nextstep) unconditionally.  Otherwise, the build picks up system
libraries and builds a mac app, which does not match the PLIST, and is
not console-only as intended.

(The CONFIGURE_ARGS disabling scheme is inconsistent between emacs
version, but this is a minimal build fix during freeze.)