patch 8.0.0600: test_recover fails on some systems

Problem:    test_recover fails on some systems.
Solution:   Explicitly check if "/" is writable. (Ken Takata)

patch 8.0.0599: diff mode is insufficiently tested

Problem:    diff mode is insufficiently tested
Solution:   Add more test cases. (Dominique Pelle, closes vim#1685)

patch 8.0.0598: building with gcc 7.1 yields new warnings

Problem:    Building with gcc 7.1 yields new warnings.
Solution:   Initialize result. (John Marriott)

patch 8.0.0597: off-by-one error in size computation

Problem:    Off-by-one error in buffer size computation.
Solution:   Use ">=" instead of ">". (Lemonboy, closes vim#1694)

patch 8.0.0596: crash when complete() called after complete_add()

Problem:    Crash when complete() is called after complete_add() in
            'completefunc'. (Lifepillar)
Solution:   Bail out if compl_pattern is NULL. (closes vim#1668)
            Also avoid using freed memory.

patch 8.0.0595: Coverity warning for not checking return value

Problem:    Coverity warning for not checking return value of dict_add().
Solution:   Check the return value for FAIL.

patch 8.0.0594: build failure when windows feature is missing

Problem:    Build failure when windows feature is missing.
Solution:   Add #ifdef.

patch 8.0.0593: duplication of code for adding a list or dict return …

…value

Problem:    Duplication of code for adding a list or dict return value.
Solution:   Add rettv_dict_set() and rettv_list_set(). (Yegappan Lakshmanan)

patch 8.0.0592: if a job writes to a buffer screen is not updated

Problem:    If a job writes to a buffer and the user is typing a command, the
            screen isn't updated. When a message is displayed the changed
            buffer may cause it to be cleared. (Ramel Eshed)
Solution:   Update the screen and then the command line if the screen didn't
            scroll. Avoid inserting screen lines, as it clears any message.
            Update the status line when the buffer changed.

patch 8.0.0591: changes to eval functionality not documented

Problem:    Changes to eval functionality not documented.
Solution:   Include all the changes.