Odd build error in 1.85 pre-release - filesystem

From: Tom Kent (lists_at_[hidden])
Date: 2024-02-23 02:07:47

When building for windows against the 1.85.0 nightly snapshot, I'm seeing
an odd error with no info around it:

    - type_erasure             : building
    - url                      : building
    - wave                     : building

...patience...
...patience...
...patience...
...patience...
...patience...
...patience...
...patience...
[errno 22] failed to scan file '': Invalid argument...found 39744 targets...

Upping the verbosity in B2, I was able to find that it appears to happen in
filesystem:

bind --
 <object(c-scanner)@8602>boost\filesystem\detail\type_traits\disjunction.hpp:
boost\filesystem\detail\type_traits\disjunction.hpp
time --
 <object(c-scanner)@8602>boost\filesystem\detail\type_traits\disjunction.hpp:
2024-02-22 07:18:09.000000000 +0000
make --
<object(c-scanner)@8602>boost\filesystem\detail\type_traits\disjunction.hpp
make --
<object(c-scanner)@8602>boost\filesystem\detail\type_traits\disjunction.hpp
time --
<object(c-scanner)@8602>boost\filesystem\detail\type_traits\disjunction.hpp:
unbound
made stable
 <object(c-scanner)@8602>boost\filesystem\detail\type_traits\disjunction.hpp
make --
 <object(c-scanner)@8602>boost\filesystem\detail\header.hpp
make --
 <object(c-scanner)@8602>boost\filesystem\detail\header.hpp
bind --               [errno 22] failed to scan file '': Invalid argument
<object(c-scanner)@8602>boost\filesystem\detail\header.hpp:
boost\filesystem\detail\header.hpp
time --
 <object(c-scanner)@8602>boost\filesystem\detail\header.hpp: 2024-02-22
07:18:09.000000000 +0000
make --
<object(c-scanner)@8602>boost\filesystem\detail\header.hpp
make --
<object(c-scanner)@8602>boost\filesystem\detail\header.hpp
time --
<object(c-scanner)@8602>boost\filesystem\detail\header.hpp: unbound
made stable
 <object(c-scanner)@8602>boost\filesystem\detail\header.hpp

Anyone have ideas on what this can be? Why it doesn't show up more like a
normal error?

Thanks,
Tom