Hi Basaku
I can't find the gecekondu in either of my English dictionaries.
Maybe Basaku could give us the reference of the English dictionary where this word has been accepted as English.
Even if Basaku does give references for this word, I prefer a translation of the word until it becomes more of a "household" term.
Most English speakers would need a copy of Basaku's dictionary close to them in order to understand the text if we use the Turkish term, which would rather spoil the reading as the "gecekondu" are essential to the translation.
If there are no other problems, I will validate
Bises
Tantine