Windows PSCP now links against winsftp.c, and scp.c is now a

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]

winmisc.c

@@ -39,6 +39,21 @@ int filename_is_null(Filename fn)
     return !*fn.path;
 }
 
+char *get_username(void)
+{
+    DWORD namelen;
+    char *user;
+
+    namelen = 0;
+    if (GetUserName(NULL, &namelen) == FALSE)
+	return NULL;
+
+    user = snewn(namelen, char);
+    GetUserName(user, &namelen);
+
+    return user;
+}
+
 int SaneDialogBox(HINSTANCE hinst,
 		  LPCTSTR tmpl,
 		  HWND hwndparent,