Support, on Unix only (so far), for OpenSSH-style generic proxying

(running a local command in a pair of pipes and proxying through
that, for example `ssh proxyhost nc -q0 %host %port').

[originally from svn r3164]

Recipe

@@ -118,11 +118,11 @@ SFTP     = sftp int64 logging
 # Miscellaneous objects appearing in all the network utilities (not
 # Pageant or PuTTYgen).
 WINMISC  = misc version winstore settings tree234 winnet proxy cmdline
-         + windefs winmisc
+         + windefs winmisc pproxy
 UXMISC   = misc version uxstore settings tree234 uxsel uxnet proxy cmdline
-         + uxmisc
+         + uxmisc uxproxy
 MACMISC  = misc version macstore settings tree234 macnet mtcpnet otnet proxy
-         + macmisc macabout
+         + macmisc macabout pproxy
 
 # Character set library, for use in pterm.
 CHARSET  = sbcsdat slookup sbcs utf8 toucs fromucs xenc mimeenc macenc localenc

config.c

@@ -1296,14 +1296,14 @@ void setup_config_box(struct controlbox *b, struct sesslist *sesslist,
 		      "Options controlling proxy usage");
 
 	s = ctrl_getset(b, "Connection/Proxy", "basics", "Proxy basics");
-	ctrl_radiobuttons(s, "Proxy type:", NO_SHORTCUT, 4,
+	ctrl_radiobuttons(s, "Proxy type:", 't', 4,
 			  HELPCTX(proxy_type),
 			  dlg_stdradiobutton_handler,
 			  I(offsetof(Config, proxy_type)),
-			  "None", 'n', I(PROXY_NONE),
-			  "HTTP", 't', I(PROXY_HTTP),
-			  "SOCKS", 's', I(PROXY_SOCKS),
-			  "Telnet", 'l', I(PROXY_TELNET),
+			  "None", I(PROXY_NONE),
+			  "HTTP", I(PROXY_HTTP),
+			  "SOCKS", I(PROXY_SOCKS),
+			  "Telnet", I(PROXY_TELNET),
 			  NULL);
 	ctrl_columns(s, 2, 80, 20);
 	c = ctrl_editbox(s, "Proxy hostname", 'y', 100,

pproxy.c

@@ -0,0 +1,17 @@
+/*
+ * pproxy.c: dummy implementation of platform_new_connection(), to
+ * be supplanted on any platform which has its own local proxy
+ * method.
+ */
+
+#include "putty.h"
+#include "network.h"
+#include "proxy.h"
+
+Socket new_connection(SockAddr addr, char *hostname,
+		      int port, int privport,
+		      int oobinline, int nodelay, Plug plug,
+		      const Config *cfg)
+{
+    return NULL;
+}