Preprocessor update

— do not allow the estimation of a parameter that appears in
  “planner_discount” (#1173)
— macro processor: fix bug in file reported when error encountered after a file
  has been included (preprocessor#42)

preprocessor @ c4a9f93d

-Subproject commit ee972d96388d0d8482d92bafc81daef49e3036d5
+Subproject commit c4a9f93d40abd4747a1101116729400452dfe9a3