Update README.windows.md

added supporting information in cases when packages are failing to build in Windows
Windows: Don't test ispath on deleted file or dir

These are failing with "stat: operation not permitted (EPERM)". There may still be
file handles open so the unlinked file and removed directory cannot be stat-ed.
Added mark/unmark/reset/ismarked to IOStream, IOBuffer, and AsyncStream
Also added show() for IOBuffer.

* Define mark, reset, unmark, ismarked for IO only.
  This is slightly sketchy, as it assumes that IO.mark exists, but
  is perhaps better than duplicating the code for all subtypes.
Fix rare and unlikely early free

During bootsrap, some code called the generic "map"
triggering compilation of the inference code in
jl_apply_generic -> jl_mt_assoc_by_type ->
cache_method. This particular map method gets
overwritten in the process and by the time
jl_apply_generic gets its function pointer back, it
is not present in the method table anymore.
Then, in jl_trampoline, compilation allocates some
managed memory, sometimes triggering GC, thus
sometimes freeing the function object before it is
called.
fix missing root on module allocation
Remove UNDOCUMENTED.rst from docs
fix #5154 (nested for loop syntax & break behavior)
Add lyap() and sylvester().
Test for lyap() and sylvester()
and taking some tests out of the inner loop in linalg1.jl
Fix: Scale is real
Doc for lyap() and sylvester().
Avoid explicit transposes
Names the actual script that gets run by Pkg.build
reverts mistaken grammatical change
Fix #7426
Fix #7461
Merge pull request #7460 from JuliaLang/sjk/steprange

Fix #7426, StepRange iteration bug
cast to unsigned char for each use of isspace
REPL: fix history_prev

Was broken by tracking the wrong key_repeats.
This introduces a function to temporarily stack away the key repeats
counter.
Bump Rmath