how to compile plugin

[Morico Stéphane]

I have an compilation error :

sample.c: In function `xfce_control_class_init':
sample.c:150: error: `sample_create_options' undeclared (first use in 
this function)
sample.c:150: error: (Each undeclared identifier is reported only once
sample.c:150: error: for each function it appears in.)
make: *** [libsample_la-sample.lo] Erreur 1

$ls
libsample_la-sample.loT  Makefile  Makefile.am  Makefile.in  sample.c