Fix "'findstr' is not recognized as ..."

[venimus]

Make sure findstr is discoverable

In certain cases findstr could not be found in path (ie command is executed by an external process which does not properly import env).

For instance bundling an app with https://github.com/achadwick/styrene + relx (ref aeternity#4 )

Styrene overrides the default path variable removing the Windows\System32 entry which makes findstr unavailable when script is executed from the launcher aeternity.exe resulting in:

'findstr' is not recognized as an internal or external command,
operable program or batch file.
'findstr' is not recognized as an internal or external command,
operable program or batch file.
'findstr' is not recognized as an internal or external command,
operable program or batch file.
test.cmd exited with status 0.
Press return to close this window.

rel: achadwick/styrene#23

Patch just adds %SystemRoot%\System32 in %PATH% + turn off command echo (some commands miss the @)

Alternative fix could be to replace all occurrences of findstr with %SystemRoot%\System32\findstr

[tsloughter]

Thanks. I'm guessing this is fine, but will first try to get someone with windows to take a look :)

[tsloughter]

And actually, @venimus do you have any thoughts on this other open PR #719

I'd like to get both of these taken care of today so I can publish a new version.

[venimus]

Actually I use the forked version https://github.com/aeternity/relx which already includes the fix and it works properly on windows 10.

https://github.com/aeternity/relx/blob/master/priv/templates/extended_bin_windows#L50

fix is already applied by @tolbrino there

[venimus]

to get more info -> https://ss64.com/nt/for_cmd.html

here in the for cycle there is 'backquote' flag (ie. usebackq) specified to escape the command (i guess because %vm_args% might include quotes and the variable is expanded before passing to findstr ).
Currently the command is wrapped by single quotes which makes the flag useless in the first place. However to properly escape the command back quotes should be used because of %vm_args%. So that fix seems logical to me.

[tsloughter]

Great, thanks!

[tolbrino]

@venimus I seem to have forgotten to create a PR for this. 👍