This introduces a primitive (RENAME-FILE) which takes C-strings as
arguments. The conversion from Forth-strings to C-strings is done in
Forth code as it doesn't seem to be any easier to do it in C.
* csrc/pf_io.h (sdRenameFile): New. It has the same semantics as
rename(2) from <stdio.h>
* csrc/pf_io.c (sdRenameFile): New stub.
* csrc/pf_guts.h (cforth_primitive_ids): ID_FILE_RENAME added,
ID_RESERVED12 removed
* csrc/pf_inner.c: Add case for ID_FILE_RENAME.
* csrc/pfcompil.c (pfBuildDictionary): Create entry for (RENAME-FILE).
* fth/file.fth (RENAME-FILE): New.
(THROW_RENAME_FILE): New constant.
* fth/t_file.fth: Remove stub and uncomment some tests.