[Bug-readline] MinGW compilation warnings in readline's input.c

[Eli Zaretskii]

When compiling Readline (as part of GDB) with MinGW on MS-Windows, I
see the following warnings:

     gcc -c -DHAVE_CONFIG_H    -I. -I. -DRL_LIBRARY_VERSION='"6.2"' -O2 
-gdwarf-4 -g3 -D__USE_MINGW_ACCESS input.c
     input.c: In function 'rl_gather_tyi':
     input.c:252:33: warning: implicit declaration of function '_kbhit' 
[-Wimplicit-function-declaration]
         chars_avail = isatty (tty) ? _kbhit () : 0;
                                      ^
     input.c: In function 'rl_getc':
     input.c:501:10: warning: implicit declaration of function '_getch' 
[-Wimplicit-function-declaration]
       return (_getch ());
               ^

The solution is to include the system header which declares the
respective prototypes:

diff --git a/input.c b/input.c
index 24126ea..e19fa85 100644
--- a/input.c
+++ b/input.c
@@ -98,6 +98,7 @@ static int rl_gather_tyi PARAMS((void));
 /* Windows isatty returns true for every character device, including the null
    device, so we need to perform additional checks. */
 #if defined (_WIN32) && !defined (__CYGWIN__)
+#include <conio.h>
 #include <io.h>
 #define WIN32_LEAN_AND_MEAN 1
 #include <windows.h>