for recognition with mapflag.
2 - A few bugs are removed in connection with argument passing to the
linker (unrecognized flags and libraries).
3 - The setting of RTS, HEAD and TAIL is done directly after the
path determination for each file.
taken over by several other keywords: stdin, stdout, prep, optimizer,
combiner and linker.
2 - The search order is changed. First {EM}/lib/{M}/descr, then
{EM}/lib/ack/{M}, finally {M}.
2 - Recognize the fact that it is possible to start a combiner without
input files.
3 - Removed -d flag. Overflow for -v (>2) now ends up in debug.
-v may be followed by a number indicating the increment.
a - a stopsuffix is indicated and met,
b - the last transformation is included in the transformation path.
2 - Maintains a 'cash' of best paths for all transformation to be executed.
2 - The overall scheme is altered.
first, all input files are processed until a combining phase is met.
then, all the combining phases are executed, the resulting files
are again processed until a combiner (or final) phase is met.
3 - The EM_DIR shell variable can be used to set ack's idea of the EM
home directory.
'hex' is the pid of the current invocation of ack in hex.
'unique' is a tail unique to this invocation.
2 - The outfile field is used to indicate default naming, can be ovrrriden
by the -o flag.
3 - Added handling for phases with multiple inputs (ego, linker).
would not need to be fed through a pre-processor.
This assumption proved false. Ack was altered and allows
use of a pre-processor on files produced by other passes.
