Make it easier to build with Lua.  Remove compiler warnings.
diff --git a/src/if_lua.c b/src/if_lua.c
index d05c1e3..133f2fc 100644
--- a/src/if_lua.c
+++ b/src/if_lua.c
@@ -921,7 +921,7 @@
 }
 
     static int
-luaV_beep(lua_State *L)
+luaV_beep(lua_State *L UNUSED)
 {
     vim_beep();
     return 0;
@@ -955,8 +955,8 @@
 		{
 		    if (l == 0) break;
 		}
-		else if (strncmp(s, buf->b_ffname, l) == 0
-			|| strncmp(s, buf->b_sfname, l) == 0)
+		else if (strncmp(s, (char *)buf->b_ffname, l) == 0
+			|| strncmp(s, (char *)buf->b_sfname, l) == 0)
 		    break;
 	    }
 	}