Problem Compiling C-functions

hallo,

I'm trying to compile the c-function refint.c in the directory
/usr/src/postgresql-6.5/contrib/spi/refint.c

when I call the compiler with the followingarguments:

gcc -I /usr/src/packages/postgresql-6.5/src/include -I
/usr/local/pgsql/include -I
/usr/src/packages/postgresql-6.5/src/backend/ -o refint.o refint.c

I get the following Error Messsages:

/usr/lib/crt1.o: In function `_start':
/usr/lib/crt1.o(.text+0x5a): undefined reference to `main'
/tmp/cca000961.o: In function `check_primary_key':
/tmp/cca000961.o(.text+0x1b): undefined reference to
`CurrentTriggerData'
/tmp/cca000961.o(.text+0x2a): undefined reference to `elog'
/tmp/cca000961.o(.text+0x32): undefined reference to
`CurrentTriggerData'
/tmp/cca000961.o(.text+0x47): undefined reference to `elog'
/tmp/cca000961.o(.text+0x4f): undefined reference to
`CurrentTriggerData'
/tmp/cca000961.o(.text+0x5d): undefined reference to
`CurrentTriggerData'
/tmp/cca000961.o(.text+0x71): undefined reference to
`CurrentTriggerData'
/tmp/cca000961.o(.text+0x87): undefined reference to `elog'
/tmp/cca000961.o(.text+0x91): undefined reference to
`CurrentTriggerData'
/tmp/cca000961.o(.text+0x9c): undefined reference to
`CurrentTriggerData'
/tmp/cca000961.o(.text+0xe1): undefined reference to `elog'
/tmp/cca000961.o(.text+0x116): undefined reference to
`CurrentTriggerData'
/tmp/cca000961.o(.text+0x12b): undefined reference to
`CurrentTriggerData'
/tmp/cca000961.o(.text+0x134): undefined reference to `SPI_connect'
/tmp/cca000961.o(.text+0x14f): undefined reference to `elog'
/tmp/cca000961.o(.text+0x164): undefined reference to
`CurrentMemoryContext'
/tmp/cca000961.o(.text+0x16a): undefined reference to
`MemoryContextAlloc'
/tmp/cca000961.o(.text+0x1c4): undefined reference to
`CurrentMemoryContext'
/tmp/cca000961.o(.text+0x1ca): undefined reference to
`MemoryContextAlloc'
/tmp/cca000961.o(.text+0x208): undefined reference to `SPI_fnumber'
/tmp/cca000961.o(.text+0x21f): undefined reference to `SPI_getrelname'
/tmp/cca000961.o(.text+0x244): undefined reference to `elog'

.... and so on

Who can help me. I need the function for the foreign key urgent.

thanks. dieter