Initial checkin of a native Mac OS X port, sharing most of its code

with the Unix port and layering a Cocoa GUI on top. The basics all
work: there's a configuration panel and a terminal window, the
timing interface works and the select interface functions. The same
application can run both SSH (or other network) connections and
local pty sessions, and multiple sessions in the same process are
fully supported.

However, it's horribly unfinished in a wide variety of other ways;
anyone interested is invited to read README.OSX and wince at the
length and content of its `unfinished' list.

[originally from svn r5308]

macosx/osx.h

@@ -0,0 +1,34 @@
+#ifndef PUTTY_OSX_H
+#define PUTTY_OSX_H
+
+/*
+ * Cocoa defines `FontSpec' itself, so we must change its name.
+ * (Arrgh.)
+ */
+#define FontSpec FontSpec_OSX_Proof
+
+/*
+ * Define the various compatibility symbols to make uxpty.c compile
+ * correctly on OS X.
+ */
+#define BSD_PTYS
+#define OMIT_UTMP
+#define HAVE_NO_SETRESUID
+#define NOT_X_WINDOWS
+
+/*
+ * OS X is largely just Unix, so we can include most of this
+ * unchanged.
+ */
+#include "unix.h"
+
+/*
+ * Functions exported by osxsel.m. (Both of these functions are
+ * expected to be called in the _main_ thread: the select subthread
+ * is an implementation detail of osxsel.m and ideally should not
+ * be visible at all outside it.)
+ */
+void osxsel_init(void);		       /* call this to kick things off */
+void osxsel_process_results(void);     /* call this on receipt of a netevent */
+
+#endif