platform-independent source file. Haven't yet added the extra
abstraction routines to uxsftp.c to create a Unix PSCP port, but it
shouldn't take long.
Also in this checkin, a change of semantics in platform_default_s():
now strings returned from it are expected to be dynamically allocated.
[originally from svn r3420]
... here's a Unix port of PSFTP. Woo. (Oddly PSCP looks to be
somewhat harder; there's more Windows code interleaved than there
was in PSFTP.)
[originally from svn r3419]