$Completion_clc = {
 
    param($commandName, $parameterName, $wordToComplete, $commandAst, $fakeBoundParameter)

    (invoke-expression "$parameterName --generate-bash-completion").Split(" ") |
    ForEach-Object {
        New-Object System.Management.Automation.CompletionResult $_, $_, 'ParameterValue', ('{0} ({1})' -f $_, $_)
    }
}

# Register the handler.
if (-not $global:options) {
    $global:options = @{CustomArgumentCompleters = @{};NativeArgumentCompleters = @{}}
}
$global:options['NativeArgumentCompleters']['clc.exe'] = $Completion_clc

# Override tabexpansion2. 
$function:tabexpansion2 = $function:tabexpansion2 -replace
    'End\r\n{',
    'End { if ($null -ne $options) { $options += $global:options} else {$options = $global:options}'

$Completion_clc = {
 
    param($commandName, $parameterName, $wordToComplete, $commandAst, $fakeBoundParameter)

    (invoke-expression "$parameterName --generate-bash-completion").Split("`n") |
    ForEach-Object {
        if ($_ -like '* *') {
            "'$_'"
        } else {
            $_
        }
    } |
    ForEach-Object {
        New-Object System.Management.Automation.CompletionResult $_, $_, 'ParameterValue', ('{0} ({1})' -f $_, $_)
    }
}

# Register the handler.
if (-not $global:options) {
    $global:options = @{CustomArgumentCompleters = @{};NativeArgumentCompleters = @{}}
}
$global:options['NativeArgumentCompleters']['clc.exe'] = $Completion_clc

# Override tabexpansion2. 
$function:tabexpansion2 = $function:tabexpansion2 -replace
    'End\r\n{',
    'End { if ($null -ne $options) { $options += $global:options} else {$options = $global:options}'

Split autocomplete options by newline and enclose multiword options in quotes
Split autocomplete options by newline and enclose multiword options in quotes

That is how PowerShell composes arguments - if it is enclosed in quotes it is treated as a single one
