refactor uwrite_heap.c, to prevent c compiler warnings, include string.h and...

refactor uwrite_heap.c, to prevent c compiler warnings, include string.h and unistd.h for strcat and readlink prototypes and add ew_print_string prototype

uwrite_heap.c

 
 #include <stdio.h>
+#include <string.h>
+#include <unistd.h>
 
 struct heap_info {
 	int *heap1_begin;
@@ -20,6 +22,8 @@ struct heap_info {
 	int array_descriptor;
 };
 
+extern void ew_print_string (char *);
+
 static int heap_written_count=0;
 
 #define MAX_N_HEAPS 10