Sorry for the long URL, but we can download the patch that KDE used for libssh 0.5.3 here: http://code.ohloh.net/project?pid=bnCaBd3Jo9I&prevcid=1&did=portage%2Fwin32libs%2Flibssh&cid=9zDTNiYDvV0&fp=305438&projSelected=true
Based on the dates in the files, 0001-implement-support-for-putty-s-pageant-0.5.3.patch supercedes 0001-implement-support-for-putty-s-pageant.patch