Add some missing #includes.

My experimental build with clang-cl at -Wall did show up a few things
that are safe enough to fix right now. One was this list of missing
includes, which was causing a lot of -Wmissing-prototype warnings, and
is a real risk because it means the declarations in headers weren't
being type-checked against the actual function definitions.

Happily, no actual mismatches.

windows/no-jump-list.c

@@ -3,6 +3,8 @@
  * that don't update the jump list.
  */
 
+#include "putty.h"
+
 void add_session_to_jumplist(const char * const sessionname) {}
 void remove_session_from_jumplist(const char * const sessionname) {}
 void clear_jumplist(void) {}