Use the "RunMe1st" file (it is an Obey file) to convert all the files from
"filename/[chs]" to "[chs].filename" (so that Zip could be easily compiled
under RISC OS). It will also set the correct makefile.

To compile just set the CSD to the main zip directory and run 'amu'.

Currently only the Acorn C V5 compiler has been tested but probably also
Acorn C V4 and the Acorn Assembler V2 will be able to compile zip.
