Extended find_suffix to accept an argument indicating the length of the
suffix string to search for.
Updated to cope with the new argument list for find_suffix.
Added support for new .SUFFIXES directives.
Added support for .SUFFIXES_DELETE directive.
Changed find_suffix to be case-insensitive.  This may need reviewing at some
point due to the inconsistent state of the case-sensitive support.
Added new messages for extended SUFFIXES directives.
Correct FAO directives for new SUFFIXES messages.  Re-generate C header
file for message constants.
Add definition of create_suffix.
Add create_suffix.
Fixed find_suffix to compare length before attempting comparison of
string.
Add definition for set_mmssuffixes.
Add set_mmssuffixes.
Adjusted Build_Suffix_List to call set_mmssuffixes.
Completed changes in description file parser to cope with  new suffixes
directives; .SUFFIXES_AFTER, .SUFFIXES_BEFORE and .SUFFIXES_DELETE.
Changed Define_Symbol to allow inclusion of a separator when appending
a value.
Changes to cope with the new handling of appending to symbols values in
Define_Symbol.
Correct signedness typo.
Corrections to the way MMSTARGETS was being defined.
Fixed the definition of MMSSUFFIXES.
Add in call to define MMSSUFFIXES before parsing description file.