Fix issues brought up in nickm's review.

 * Update pt_get_proxy_uri() documentation.
 * proxy_supported is now unsigned.
 * Added a changes file.

changes/bug8402

@@ -0,0 +1,5 @@
+  o Major features (bridges):
+    - Expose the outgoing upstream HTTP/SOCKS proxy to pluggable
+      transports if they are configured via the "TOR_PT_PROXY"
+      enviorment variable.  Implements proposal 232. Resolves
+      ticket 8402.

src/or/transports.c

@@ -754,7 +754,9 @@ managed_proxy_destroy(managed_proxy_t *mp,
   tor_free(mp);
 }
 
-/** Convert the tor proxy options to a URI suitable for TOR_PT_PROXY. */
+/** Convert the tor proxy options to a URI suitable for TOR_PT_PROXY.
+ * Return a newly allocated string containing the URI, or NULL if no
+ * proxy is set. */
 STATIC char *
 get_pt_proxy_uri(void)
 {

src/or/transports.h

@@ -82,7 +82,7 @@ typedef struct {
   int conf_protocol; /* the configuration protocol version used */
 
   char *proxy_uri;  /* the outgoing proxy in TOR_PT_PROXY URI format */
-  int proxy_supported : 1; /* the proxy claims to honor TOR_PT_PROXY */
+  unsigned int proxy_supported : 1; /* the proxy honors TOR_PT_PROXY */
 
   int is_server; /* is it a server proxy? */