[PATCH] pg_filedump is broken

Hello.

First patch fixes:

```
pg_filedump.c: In function ‘FormatItem’:
pg_filedump.c:994:18: error: ‘SizeOfIptrData’ undeclared (first use in
                      this function)
   if (numBytes < SizeOfIptrData)
```

After 8023b582 there is no more SizeOfIptrData macro.

Second patch fixes Makefile. On some systems (notably FreeBSD) there is
no `gcc` by default. Using `cc` is a more crossplatform way to compile a
project.

--
Best regards,
Aleksander Alekseev