input: look at the modifier keys only when compiled on Linux

This fixes https://savannah.gnu.org/bugs/?48751 reported by Andrew Ho.

This also fixes compilation when configured with --enable-tiny.

src/global.c

@@ -33,8 +33,11 @@ volatile sig_atomic_t sigwinch_counter = 0;
 	/* Is incremented by the handler whenever a SIGWINCH occurs. */
 #endif
 
+#if defined(__linux__) && !defined(NANO_TINY)
 bool console;
 	/* Whether we're running on a Linux VC (TRUE) or under X (FALSE). */
+#endif
+
 bool meta_key;
 	/* Whether the current keystroke is a Meta key. */
 bool focusing = TRUE;

src/nano.c

@@ -2482,9 +2482,10 @@ int main(int argc, char **argv)
     /* Set up the terminal state. */
     terminal_init();
 
+#if defined(__linux__) && !defined(NANO_TINY)
     /* Check whether we're running on a Linux console. */
     console = (getenv("DISPLAY") == NULL);
-
+#endif
 #ifdef DEBUG
     fprintf(stderr, "Main: set up windows\n");
 #endif

src/proto.h

@@ -30,7 +30,10 @@
 extern volatile sig_atomic_t sigwinch_counter;
 #endif
 
+#if defined(__linux__) && !defined(NANO_TINY)
 extern bool console;
+#endif
+
 extern bool meta_key;
 extern bool focusing;
 

src/winio.c

@@ -23,7 +23,9 @@
 #include "proto.h"
 #include "revision.h"
 
+#if defined(__linux__) && !defined(NANO_TINY)
 #include <sys/ioctl.h>
+#endif
 
 #include <stdio.h>
 #include <stdarg.h>
@@ -504,6 +506,7 @@ int parse_kbinput(WINDOW *win)
 	return sc_seq_or(do_next_block, 0);
 #endif
 
+#if defined(__linux__) && !defined(NANO_TINY)
     /* When not running under X, check for the bare arrow keys whether
      * the Ctrl key is being held together with them. */
     if (console && (retval == KEY_UP || retval == KEY_DOWN ||
@@ -521,6 +524,7 @@ int parse_kbinput(WINDOW *win)
 		return sc_seq_or(do_next_word_void, 0);
 	}
     }
+#endif /* __linux__ && !NANO_TINY */
 
     switch (retval) {
 #ifdef KEY_SLEFT