Problem:    JSON encoding could be faster.
Solution:   Optimize encoding JSON strings. (closes #10086)

Problem:    Avoidance of #elif causes more preproc nesting.
Solution:   Use #elif where it is useful. (Ozaki Kiichi, closes #10081)

Problem:    new regexp does not accept pattern "\%>0v".
Solution:   Do accept digit zero.

Problem:    No test for what 8.2.4691 fixes.
Solution:   Add a test.  Use a more generic sotlution. (closes #10090)

Problem:    Solution for <Cmd> in a mapping causes trouble.
Solution:   Use another solution: put back CTRL-O after reading the <Cmd>
            sequence.

Problem:    Channel tests fail on MS-Windows.
Solution:   Check if the AF_UNIX attribute exists. (closes #10083)

Problem:    Using <Cmd> in a mapping does not work for mouse keys in Insert
            mode. (Sergey Vlasov)
Solution:   When reading the <Cmd> argument do not use the stuff buffer.
            (closes #10080)

Problem:    New regexp engine does not give an error for "\%v".
Solution:   Check for a value argument. (issue #10079)

Problem:    "vimgrep /\%v/ *" may cause a crash.
Solution:   When compiling the pattern with the old engine fails, restore the
            regprog of the new engine instead of leaving it NULL.
            (closes #10079)

Problem:    Configure doesn't find the Motif library with Cygwin.
Solution:   Check for libXm.dll.a. (Kelvin Lee, closes #10077)