Assorted benign warning fixes.

These were just too footling for even me to bother splitting up into
multiple commits:

 - a couple of int -> size_t changes left out of the big-bang commit
   0cda34c6f

 - a few 'const' added to pointer-type casts that are only going to be
   read from (leaving out the const provokes a warning if the pointer
   was const _before_ the cast)

 - a couple of 'return' statements trying to pass the void return of
   one function through to another.

 - another missing (void) in a declaration in putty.h (but this one
   didn't cause any knock-on confusion).

 - a few tweaks to macros, to arrange that they eat a semicolon after
   the macro call (extra do ... while (0) wrappers, mostly, and one
   case where I had to do it another way because the macro included a
   variable declaration intended to remain in scope)

 - reworked key_type_to_str to stop putting an unreachable 'break'
   statement after every 'return'

 - removed yet another type-check of a function loaded from a Windows
   system DLL

 - and finally, a totally spurious semicolon right after an open brace
   in mainchan.c.

1 files changed, 2 insertions, 3 deletions

diff --git a/cmdline.c b/cmdline.c
index b9d068f6..8f656e53 100644
--- a/cmdline.c
+++ b/cmdline.c
@@ -858,9 +858,8 @@ int cmdline_process_param(const char *p, char *value,
 
 void cmdline_run_saved(Conf *conf)
 {
-    int pri, i;
-    for (pri = 0; pri < NPRIORITIES; pri++) {
-        for (i = 0; i < saves[pri].nsaved; i++) {
+    for (size_t pri = 0; pri < NPRIORITIES; pri++) {
+        for (size_t i = 0; i < saves[pri].nsaved; i++) {
             cmdline_process_param(saves[pri].params[i].p,
                                   saves[pri].params[i].value, 0, conf);
             sfree(saves[pri].params[i].p);