Stop using unqualified {GET,PUT}_32BIT.

Those were a reasonable abbreviation when the code almost never had to
deal with little-endian numbers, but they've crept into enough places
now (e.g. the ECC formatting) that I think I'd now prefer that every
use of the integer read/write macros was clearly marked with its
endianness.

So all uses of GET_??BIT and PUT_??BIT are now qualified. The special
versions in x11fwd.c, which used variable endianness because so does
the X11 protocol, are suffixed _X11 to make that clear, and where that
pushed line lengths over 80 characters I've taken the opportunity to
name a local variable to remind me of what that extra parameter
actually does.

ssh2bpp-bare.c

@@ -170,7 +170,7 @@ static void ssh2_bare_bpp_format_packet(struct ssh2_bare_bpp_state *s,
 
     s->outgoing_sequence++;        /* only for diagnostics, really */
 
-    PUT_32BIT(pkt->data, pkt->length - 4);
+    PUT_32BIT_MSB_FIRST(pkt->data, pkt->length - 4);
     bufchain_add(s->bpp.out_raw, pkt->data, pkt->length);
 }