keys.c: disable -Warray-bounds warning from gcc >= 8. seems bogus.

keys.c: In function 'Char_Console':
keys.c:469:4: warning: 'memmove' offset [-2147483647, -1] is out of the bounds [0, 16384] of object 'key_lines' with type 'char[64][256]' [-Warray-bounds]
    memmove (workline + 1, workline, len);
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
keys.c:31:7: note: 'key_lines' declared here
 char  key_lines[CMDLINES][MAXCMDLINE];
       ^~~~~~~~~

Quake/keys.c

@@ -466,7 +466,13 @@ void Char_Console (int key)
 			workline[MAXCMDLINE - 2] = 0;
 			workline += key_linepos;
 			len = strlen(workline) + 1;
+			#if defined(__GNUC__) && (__GNUC__ > 7)
+			#pragma GCC diagnostic ignored "-Warray-bounds"
+			#endif
 			memmove (workline + 1, workline, len);
+			#if defined(__GNUC__) && (__GNUC__ > 7)
+			#pragma GCC diagnostic pop
+			#endif
 			*workline = key;
 		}
 		else