[isabelle-dev] NEWS: isabelle build options

[Makarius]

*** System ***

* Command-line tool "isabelle build" supports new options:
  - option -B NAME: include session NAME and all descendants
  - option -S: only observe changes of sources, not heap images
  - option -f: forces a fresh build

* Command-line tool "isabelle build" takes "condition" options with the
corresponding environment values into account, when determining the
up-to-date status of a session.


This is the updated situation according to Isabelle/be08a7691c62.


	Makarius