Changes need to be done for IDEA to work on solaris 2.8 due to sys/types.h and LITTLE_ENDIAN 

1. vi idea.h and change all u_int16_t to uint16_t
2. vi _idea.c and change the following to items
   a. change "#include <endian.h>" to "#include <arpa/nameser_compat.h>
   b. change all u_int16_t to uint16_t
3. vi IDEA.xs and change all u_int16_t to uint16_t

Now you can start your procedure to compile, test and install it
Hope this short note will help you
Amanda