* fix(gtk): prevent duplicate shortcut folders
This prevents duplicates if the recent destination is also a system
shortcut folder.
* refactor(gtk): create gtr_get_recent_dirs helper
* feat(gtk): remember 4 recent relocate dirs
* refactor: make this variable const
* refactor: replace redundant type with auto
* refactor: use the nullptr literal
* refactor: replace declaration by structured binding declaration
* fix: make variable a pointer-to-const
* fix: use init-statement to reduce variable scope
* fix: implicit conversion from long to int
* fix: refactor to not nest more than 3 if|for|do|while|switch statements
* fix: make tr_session::setSocketTos() const
* fix: use array.prototype.some instead of a for loop
* refactor: use nullptr instead of NULL
* fix: oops
* refactor: include <memory> when using shared_ptr or unique_ptr
* refactor: include <cstdio> iff we use it
* refactor: include <cstring> iff we use it
* refactor: include <cstdlib> iff we use it
* refactor: include <string_view> or <string> iff we use it
* refactor: include <array> iff we use it
* refactor: include <ctime> iff we use it
* refactor: include <cctype> iff we use it
* refactor: misc #include cleanups in libtransmission
* (C++) Macros should not be used to define constants
* (C++) Memory should not be managed manually
* (C++) "void*" should not be used in typedefs, member variables, function parameters or return type
* (C++) When the "Rule-of-Zero" is not applicable, the "Rule-of-Five" should be followed
* (C++) "switch" statements should have "default" clauses
* (C++) "explicit" should be used on single-parameter constructors and conversiosn operators
* (C++) Non-const global variables should not be used
bexnoss