Make 1987/lievaart slightly more like original

Restored the #define D define even though it can't be used with modern
compilers, just so it looks as close to the original as possible. This
goes for both versions, the one with the board and the entry (limited by
the contest restrictions).

1987/lievaart/lievaart.c

@@ -1,3 +1,4 @@
+#define D define
 #define Y return
 #define R for
 #define e while

1987/lievaart/lievaart2.c

@@ -1,3 +1,4 @@
+#define D define
 #define Y return
 #define R for
 #define e while