Windows CE port fixes/enhancements (from <Someone>)

A few other fixes:
- bug: text window does not scroll left on left arrow
- pcmain.c: fix warning: _fileno() returns void* in Windows CE SDK

3.5.0 only:
- files.c: compile error: don't include <signal.h> if NO_SIGNAL is defined. WinMo does not support POSIX signals
- version.c: compile error: append_port_id() is undeclared
- link error: mktime() is unsupported -> define it in celib.c

-<Someone>

src/files.c

@@ -45,7 +45,7 @@ extern int errno;
 #include <stdlib.h>
 #endif
 
-#if defined(UNIX) || defined(VMS) || defined(_MSC_VER)
+#if defined(UNIX) || defined(VMS) || !defined(NO_SIGNAL)
 #include <signal.h>
 #endif