And just to prove that psftp.c really is now platform-independent

... 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]

unix/unix.h

@@ -51,8 +51,6 @@ unsigned long getticks(void);	       /* based on gettimeofday(2) */
 #define WCHAR wchar_t
 #define BYTE unsigned char
 
-GLOBAL void *logctx;
-
 /* Things pty.c needs from pterm.c */
 char *get_x_display(void *frontend);
 int font_dimension(void *frontend, int which);/* 0 for width, 1 for height */
@@ -128,4 +126,13 @@ int init_ucs(struct unicode_data *ucsdata,
  */
 int sk_getxdmdata(void *sock, unsigned long *ip, int *port);
 
+/*
+ * General helpful Unix stuff: more helpful version of the FD_SET
+ * macro, which also handles maxfd.
+ */
+#define FD_SET_MAX(fd, max, set) do { \
+    FD_SET(fd, &set); \
+    if (max < fd + 1) max = fd + 1; \
+} while (0)
+
 #endif