Comment 3 for bug 493380

commit ac93aa515b197d751dad85d70432ebc87fac420a
Author: Nikodemus Siivola <email address hidden>
Date: Tue Apr 24 09:16:47 2012 +0300

    better reader-errors for COMPILE-FILE

     * Make SIMPLE-READER-PACKAGE-ERROR a subclass of PACKAGE-ERROR.

     * Make reader signal a SIMPLE-READER-PACKAGE-ERROR for missing packages,
       instead of a vanilla PACKAGE-ERROR: that way get the position reported as
       well.

     * Factor out line and column reporting logic for reader-errors into a
       separate function, and allow using other than current file position.

     * READ-FOR-COMPILE-FILE needs to use COMPILER-ERROR, and
       INPUT-ERROR-IN-COMPILE-FILE is a subclass of READER-ERROR, not a
       FATAL-COMPILER-CONDITION.

     * *COMPILER-ERROR-BAILOUT* binding in SUB-COMPILE-FILE was missing the
       condition argument from the lambda-list, and should not mumble to
       *STANDARD-OUTPUT*.

     This patch converts all input errors into COMPILE-FILE failures without
     dropping into the debugger. That might be taking things too far, though --
     but the question of "which errors should we let enter the debugger" has no
     obvious answers to me at least. Perhaps *COMPILER-HANDLED-ERRORS* is the way
     to go?

     Fixes lp#493380