Cmake build fails on Windows

[srg-kostyrko]

Changes introduced in 09fbc66 cause cmake build to fail on Windows because of the missing definition of ssize_t type

I get the following error on build

regexec.c(1103,17): error C2061: syntax error: identifier "StackIndex" 

if I revert the change introduced in commit - build works.

Commands used for the build

$ cmake -G "Visual Studio 16 2019" -A Win32 -DCMAKE_INSTALL_PREFIX=out ..
$ cmake --build . --target install --config Release

configuration step output

-- Selecting Windows SDK version 10.0.18362.0 to target Windows 10.0.18363.
-- The C compiler identification is MSVC 19.26.28806.0
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: C:/Program Files/VisualStudio/VC/Tools/MSVC/14.26.28801/bin/Hostx64/x86/cl.exe - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Looking for alloca
-- Looking for alloca - not found
-- Looking for include file alloca.h
-- Looking for include file alloca.h - not found
-- Looking for include file stdint.h
-- Looking for include file stdint.h - found
-- Looking for include file sys/times.h
-- Looking for include file sys/times.h - not found
-- Looking for include file sys/time.h
-- Looking for include file sys/time.h - not found
-- Looking for include file sys/types.h
-- Looking for include file sys/types.h - found
-- Looking for include file unistd.h
-- Looking for include file unistd.h - not found
-- Looking for include file inttypes.h
-- Looking for include file inttypes.h - found
-- Looking for stddef.h
-- Looking for stddef.h - found
-- Check size of int
-- Check size of int - done
-- Check size of long
-- Check size of long - done
-- Check size of long long
-- Check size of long long - done
-- Check size of void*
-- Check size of void* - done
-- Configuring done
-- Generating done
-- Build files have been written to: D:/projects/oniguruma/build

I'm willing to help with testing of this problem
Please let me know if you need any additional info

[asottile]

I am also seeing build errors for v6.9.6_rc1 on windows:

https://asottile.visualstudio.com/asottile/_build/results?buildId=4632&view=logs&j=0268f1ee-3a30-5926-65c4-3bada40a45a5&t=4be81aa0-7a13-52ed-304b-c9e64249c2fd

log output in case azure pipelines goes stale:

71.txt

[kkos]

Thank you.
I am currently in an environment where Windows is unavailable due to COVID-19.