compiling C Funktion for PostgreSQL

Hello,

I have a problem with the postgreSQL Source Code when I compile the
fuzzystrmatch.c. I want to try to replace all german umlauts for the soundex
algorithm. But when I want to compile the C Code, I get an error on the
following line in the fuzzystrmatch.c:

PG_MODULE_MAGIC;

And here is the error I get:

In function 'Pg_magic_func': 'PG_VERSION_NUM' undeclared (first use in
function)

The PG_VERSION_NUM is defined in the fmgr.h of the PostgreSQL Source Code:

/* Definition of the magic block structure */
typedef struct
{
int len; /* sizeof(this struct) */
int version; /* PostgreSQL major version */
int funcmaxargs; /* FUNC_MAX_ARGS */
int indexmaxkeys; /* INDEX_MAX_KEYS */
int namedatalen; /* NAMEDATALEN */
} Pg_magic_struct;

/* The actual data block contents */
#define PG_MODULE_MAGIC_DATA \
{
sizeof(Pg_magic_struct),
PG_VERSION_NUM / 100,
FUNC_MAX_ARGS,
INDEX_MAX_KEYS,
NAMEDATALEN
}

Can anyone help me to figure out this problem?

Thanks in advance

Jürgen Ulrich