68040 and 68060 owners.
With ``make M68040=1'' or ``make M68060=1'', we build a libc where the ldexp()
doesn't use excessive amounts of system cpu time.
Without any of those defines, the normal assembler version using FSCALE is
included, for the benefit of M68020 and M68030 users, or M68040/M68060 users
where the ldexp performance is no bottleneck.
[Its not yet worked out how to include both library versions in a binary
distribution, but you can build your own from source now if you need it.]
For details, look at PR 3105.
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