[Pidgin] #17291: Fix crashes when some external APIs fail

[Pidgin]

#17291: Fix crashes when some external APIs fail
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 Reporter:  Zhouyang  |       Owner:  EionRobb
     Type:  patch     |      Status:  new
Milestone:            |   Component:  libpurple
  Version:  2.12.0    |  Resolution:
 Keywords:  API bugs  |
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Comment (by EionRobb):

 It'd be really helpful if you could do this as a pull request at
 https://bitbucket.org/pidgin/main/pull-requests/ so that others can
 comment and keep track of changes.

 Another one I've just seen is that libpurple/dnsquery.c is expected to
 fail, so there shouldn't be a warning generated.

 Also, code should be run after all the function variables have been
 defined (eg the pidgin/gtkprefs.c change should be moved below the
 definition of the *next variable) as we target c89

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Ticket URL: <https://developer.pidgin.im/ticket/17291#comment:4>
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