In finch/gntaccount.c, scan-build thinks that dialog->account may change

  between the two places it is used; this is not the case, but easiest to

  placate it by using a common variable.
In finch/gntblist.c, comment out more code to limit dead stores.
In libpurple/mediamanager.c and pidgin/gtkrequest.c, a non-NULL

  initializer is used on a variable that is replaced later by the same thing,

  so just initialize to NULL instead.

Compiled with ninja scan-build.