Fix a portability issue with md_hasclreol().

Some games' implementation of md_hasclreol() poked around in ncurses
internals, which does not work for some ncurses build configuration.
Most games did not actually call md_hasclreol(), so it was removed.
There is a standard terminfo function which can retrieve the value of
the clr_eol capability, so this was used for rogue5.

rogue3/mdport.h

@@ -171,7 +171,6 @@ int	md_setdsuspchar(int c);
 int	md_shellescape(void);
 void	md_sleep(int s);
 int	md_suspchar(void);
-int	md_hasclreol(void);
 int	md_unlink(char *file);
 int	md_unlink_open_file(const char *file, FILE *inf);
 void	md_tstpsignal(void);