Cygwin workaround should only be applied if we compile with Cygwin

scrolltext/scrolltext3.c

@@ -15,7 +15,10 @@
 #include "font_arial8.h"
 // #include "font_small6.h"
 // #include "font_uni53.h"
-#define strtok_r(a, b, c) strtok((a), (b))
+
+#ifdef __CYGWIN__
+	#define strtok_r(a, b, c) strtok((a), (b))
+#endif
 
 #define MAX_FONTS 1
 font fonts[MAX_FONTS];