bug#21965: 24.5; Emacs freezes when canceling at open file

[John Wiegley]

>>>>> Eli Zaretskii <eliz@gnu.org> writes:

>> 7   libglib-2.0.0.dylib                 0x0000000100888ba1 g_mutex_lock + 26
>> 8   libglib-2.0.0.dylib                 0x000000010084c284 
>> g_main_context_acquire + 42
>> 9   emacs                               0x00000001001447cc xg_select + 135
>> 10  emacs                               0x000000010012dbe2 
>> wait_reading_process_output + 2074
>> 11  emacs                               0x00000001000075b5 sit_for + 260
>> 12  emacs                               0x000000010008be56 read_char + 5024
>> 13  emacs                               0x000000010008918c read_key_sequence 
>> + 1526

> This backtrace simply says that Emacs called 'abort'.  And it did so
> because the user told it so.

It might also be saying that Emacs deadlocked trying to obtain a mutex.

John