after make:

gcc -DHAVE_CONFIG_H -I. -I. -I.     -g -Wall -ansi -D_GNU_SOURCE -O2 -c main.c
In file included from main.c:69:
channel.h:40: error: array type has incomplete element type
channel.h:56: error: array type has incomplete element type
channel.h:57: error: array type has incomplete element type
channel.h:58: error: array type has incomplete element type
main.c: In fuction ‘set_float’:
main.c:566: warning: dereferencing type-punned pointer will break strict-aliasing rules
main.c: In fuction ‘grabber_init’:
main.c:1156: warning: dereferencing type-punned pointer will break strict-aliasing rules
make: *** [main.o] Error 1