I ran a nightly test with this patch included and found that it breaks several
tests, for example:

https://nightly.syncevolution.org/2014-02-15-14-15_all/testing-amd64/10-googlecalendar/Client_Sync_eds_event_testItems.log.html
...
-------------------------------------------------------------------------------
BEGIN:VCALENDAR                          BEGIN:VCALENDAR
VERSION:2.0                              VERSION:2.0
  BEGIN:VEVENT                             BEGIN:VEVENT
  SUMMARY:two day event                    SUMMARY:two day event
  DTEND;VALUE=DATE:20060408                DTEND;VALUE=DATE:20060408
  DTSTART;VALUE=DATE:20060406              DTSTART;VALUE=DATE:20060406
  UID:20060416T204047Z-4272-727-1-245  |   UID:syuid642838.212259308803453
   @gollum                             <
  END:VEVENT                               END:VEVENT
END:VCALENDAR                            END:VCALENDAR
-------------------------------------------------------------------------------

https://nightly.syncevolution.org/2014-02-15-14-15_all/testing-amd64/16-davical/Client_Sync_eds_task_testManyItems.log.html

[DEBUG 00:02:47] ClientTest.cpp:752: starting equal = config.m_compare(client,
sourceFile, copyFile)
 deleteall.init deleteall.twoway send refresh refresh twinning

Client_Sync_eds_task_testManyItems.A.test.dat |
Client_Sync_eds_task_testManyItems.B.test.dat
                     only in left file <
                                       > only in right file
-------------------------------------------------------------------------------
BEGIN:VCALENDAR                          BEGIN:VCALENDAR
VERSION:2.0                              VERSION:2.0
  BEGIN:VTODO                              BEGIN:VTODO
  SUMMARY:000-do me                        SUMMARY:000-do me
  DESCRIPTION:xxxxxxxxxxxxxxxxxxxxxxx      DESCRIPTION:xxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxx\nxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxx\nxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\nx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\nx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxx\nxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxx\nxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxx\nxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxx\nxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxx\nxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxx\nxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxx\nxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxx\nxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xx\nxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xx\nxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\nxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\nxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxx\nxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxx\nxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxx\nxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxx\nxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxx\nxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxx\nxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxx\nxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxx\nxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   x\nxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      x\nxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\nxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\nxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxx\nxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxx\nxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxx\nxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxx\nxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxx\nxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxx\nxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxx\nxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxx\nxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   \nxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      \nxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxx\nxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxx\nxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxx\nxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxx\nxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxx\nxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxx\nxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxx\nxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxx\nxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxx\nxxxxxxxxxxxxxxxxxxxxxxxxxxxx      xxxxx\nxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\      xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\
   nxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx      nxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
   xxxxxxxxxxxxxxxxxxxxxxxxxxxx\nxxxxx      xxxxxxxxxxxxxxxxxxxxxxxxxxxx\nxxxxx
   xxxxxxxxxxx\nxto be done                 xxxxxxxxxxx\nxto be done
  PRIORITY:0                               PRIORITY:0
  STATUS:NEEDS-ACTION                      STATUS:NEEDS-ACTION
  UID:syuid060245.212259327652823      |   UID:syuid125355.212259327680020
  END:VTODO                            <
END:VCALENDAR                          <
-------------------------------------------------------------------------------
...

Looks like a more complex solution will be needed. In the meantime I'll release
SyncEvolution 1.4 without this patch.