I'm sick of all those #ifdefs in settings.c, and in any case plink

and pterm need at least one default setting to be _different_ (pterm
needs the default term type to be `xterm', while plink needs it to
be taken from $TERM). So here's a completely new alternative
mechanism for platform- and app-specific default settings. Ben will
probably want to check the integrity of the Mac port, since I've
fiddled with it without testing that it still compiles.

[originally from svn r2513]

putty.h

@@ -481,6 +481,18 @@ void get_sesslist(struct sesslist *, int allocate);
 void do_defaults(char *, Config *);
 void registry_cleanup(void);
 
+/*
+ * Functions used by settings.c to provide platform-specific
+ * default settings.
+ * 
+ * (The integer one is expected to return `def' if it has no clear
+ * opinion of its own. This is because there's no integer value
+ * which I can reliably set aside to indicate `nil'. The string
+ * function is perfectly all right returning NULL, of course.)
+ */
+char *platform_default_s(char *name);
+int platform_default_i(char *name, int def);
+
 /*
  * Exports from terminal.c.
  */