1) Fix a bug where the recursion on prefixes where if recusrion failed
then the next attempt started too far along the string.
2) Up some internal limits that we were about to hit off.
3) Change the constness and signedness of some things and complete missing
prototypes.
4) Remove the readerror function 'cos it could print out the wrong
wrong file name. Replace it with more useful error messages.
5) Use sizeof when passing buffers to fgets.
6) Warn about empty prefix definitions.
Reviewed by: iedowse
This will make a number of things easier in the future, as well as (finally!)
avoiding the Id-smashing problem which has plagued developers for so long.
Boy, I'm glad we're not using sup anymore. This update would have been
insane otherwise.
