of 16 bytes. Use "sizeof" for the size of e_guid_t's, and use structure
assignment to copy GUID values.
Make functions such as append_h225ras_call() and new_h225ras_call() take
pointers to e_guid_t's as arguments.
Define GUID_LEN in epan/guid-utils.h and use it as the length of a GUID
in a packet. (Note that "sizeof e_guid_t" is not guaranteed to be 16,
although it is guaranteed to be the size of an e_guid_t.)
When constructing a display filter that matches a GUID, use
guid_to_str() to construct the string for the GUID.
svn path=/trunk/; revision=17676