Problem:    Using two counters for timeout check in NFA engine.
Solution:   Use only one counter.  Tune the counts based on guessing.

Problem:    When splitting a window the changelist position moves.
Solution:   Set the changelist index a bit later. (closes #10493)

Problem:    There is no way to get the byte index from a virtual column.
Solution:   Add virtcol2col(). (Yegappan Lakshmanan, closes #10477,
            closes #10098)

Problem:    Build error with +eval but without +quickfix.  Warning for
            uninitialized variable.
Solution:   Adjust #ifdefs. (John Marriott)

Problem:    Python 3 test fails without the GUI.
Solution:   Check the balloon_eval feature is available.

Problem:    Cannot easily run the benchmarks.
Solution:   Have "make benchmark" in the src directory work.

Problem:    autocmd_add() can only handle one event and pattern.
Solution:   Support a list of events and patterns. (Yegappan Lakshmanan,
            closes #10483)

Problem:    "textlock" is always zero.
Solution:   Remove "textlock" and rename "textwinlock" to "textlock".
            (closes #10489)

Problem:    Syntax regexp matching can be slow.
Solution:   Adjust the counters for checking the timeout to check about once
            per msec. (closes #10487, closes #2712)

Problem:    Error for missing :endif when an exception was thrown. (Dani
            Dickstein)
Solution:   Do not give an error when aborting. (closes #10490)