Don't require a key-press when exiting a UIFC app run in ANSI mode on Win32

Breaking into a debugger, I found the task was hung in:
_lock_file(stdin) called from common_flush_all(), so the stream was locked.
Simply unlocking it resolves the problem.

This bug has been around forever and was annoying but non-serious (just
required the user/sysop to hit ENTER). So happy it's now fixed.

src/conio/ansi_cio.c

@@ -999,6 +999,14 @@ int ansi_initciolib(long inmode)
 	return(1);
 }
 
+void ansi_suspend(void)
+{
+#if defined _WIN32
+	// Prevents the wait for a key press when exit() is called and the stdin stream is flushed
+	_unlock_file(stdin);
+#endif
+}
+
 CIOLIBEXPORT void CIOLIBCALL ansi_ciolib_setdoorway(int enable)
 {
 	if(cio_api.mode!=CIOLIB_MODE_ANSI)

src/conio/ansi_cio.h

@@ -70,6 +70,7 @@ int ansi_getch(void);
 int ansi_getche(void);
 void ansi_beep(void);
 void ansi_textmode(int mode);
+void ansi_suspend(void);
 #ifdef __cplusplus
 }
 #endif

src/conio/ciolib.c

@@ -322,6 +322,7 @@ static int try_ansi_init(int mode)
 		cio_api.textmode=ansi_textmode;
 		cio_api.ESCDELAY=&CIOLIB_ANSI_TIMEOUT;
 		cio_api.beep=ansi_beep;
+		cio_api.suspend=ansi_suspend;
 		return(1);
 	}
 	return(0);