[windows] Procs Wait Fix

[Mr-Emacs]

This is an issue to fix procs wait so child that is created will be inheritable from the child.

Previously:

The child process handle was not working properly

Z:\home\segfault\Programming\issex>nob.exe
[INFO] renaming nob.exe -> nob.exe.old
[INFO] CMD: cl.exe /Fe:nob.exe nob.c
[ERROR] could not wait on child process: Invalid handle.
[INFO] renaming nob.exe.old -> nob.exe

Z:\home\segfault\Programming\issex>Microsoft (R) C/C++ Optimizing Compiler Version 19.50.35729 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

nob.c
Microsoft (R) Incremental Linker Version 14.50.35729.0
Copyright (C) Microsoft Corporation.  All rights reserved.

/out:nob.exe
nob.obj

Z:\home\segfault\Programming\issex>

But now after the fix.

Z:\home\segfault\Programming\issex>
Z:\home\segfault\Programming\issex>nob.exe
[INFO] renaming nob.exe -> nob.exe.old
[INFO] CMD: cl.exe /Fe:nob.exe nob.c
Microsoft (R) C/C++ Optimizing Compiler Version 19.50.35729 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

nob.c
Microsoft (R) Incremental Linker Version 14.50.35729.0
Copyright (C) Microsoft Corporation.  All rights reserved.

/out:nob.exe
nob.obj
[INFO] CMD: nob.exe
[INFO] CMD: cl /Zi /Isrc /std:c11 /TC /DEMACS_PRINT /Feissex.exe src/main.c
Microsoft (R) C/C++ Optimizing Compiler Version 19.50.35729 for x64
Copyright (C) Microsoft Corporation.  All rights reserved.

main.c
src/main.c(482): warning C4090: 'function': different 'const' qualifiers
Microsoft (R) Incremental Linker Version 14.50.35729.0
Copyright (C) Microsoft Corporation.  All rights reserved.

/debug
/out:issex.exe
main.obj

The solution is to make the child process inheritable.

if (fdin || fdout || fderr) {
        HANDLE hStdIn  = fdin  ? *fdin  : GetStdHandle(STD_INPUT_HANDLE);
        HANDLE hStdOut = fdout ? *fdout : GetStdHandle(STD_OUTPUT_HANDLE);
        HANDLE hStdErr = fderr ? *fderr : GetStdHandle(STD_ERROR_HANDLE);
        SetHandleInformation(hStdIn,  HANDLE_FLAG_INHERIT, HANDLE_FLAG_INHERIT);
        SetHandleInformation(hStdOut, HANDLE_FLAG_INHERIT, HANDLE_FLAG_INHERIT);
        SetHandleInformation(hStdErr, HANDLE_FLAG_INHERIT, HANDLE_FLAG_INHERIT);
        siStartInfo.hStdInput  = hStdIn;
        siStartInfo.hStdOutput = hStdOut;
        siStartInfo.hStdError  = hStdErr;
        siStartInfo.dwFlags   |= STARTF_USESTDHANDLES;
    }

Then later check the exit code of each process.