patchgit-gui--askpass: coerce answers to UTF-8 on Windows

> diff --git a/git-gui--askpass b/git-gui--askpass
> index 4277f30c411..b0704e6d91e 100755
> --- a/git-gui--askpass
> +++ b/git-gui--askpass
> @@ -56,6 +56,11 @@ proc finish {} {
>  		}
>  	}
>  
> +	# On Windows, force the encoding to UTF-8: it is what `git.exe` expects
> +		if {$::tcl_platform(platform) eq {windows}} {

>  	puts $::answer
>  	set ::rc 0
>  }
>
> base-commit: 63a58457e094c9c9bbf562b872009d32f1f88133

> From: Luke Bonanomi <lbonanomi@gmail.com>
>
> This addresses the issue where Git for Windows asks the user for a
> password, no credential helper is available, and then Git fails to pick
> up non-ASCII characters from the Git GUI helper.
>
> This can be verified e.g. via
>
> 	echo host=http://abc.com |
> 	git -c credential.helper= credential fill
>
> and then pasting some umlauts.
>
> The underlying reason is that Git for Windows tries to communicate using
> the UTF-8 encoding no matter what the actual current code page is. So
> let's indulge Git for Windows and do use that encoding.
>
> This fixes https://github.com/git-for-windows/git/issues/2215
>
> Signed-off-by: Luke Bonanomi <lbonanomi@gmail.com>
> Helped-by: Junio C Hamano <gitster@pobox.com>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
> ---

>     Fix git-gui--askpass on Windows
>     
>     Windows has this odd thing where there is an active code page (somewhat
>     like LC_CTYPE) and there is no real UTF-8 code page. So we need to help 
>     git-gui--askpass along a bit to be of use when asking for credentials.
>     
>     Changes since v1:
>     
>      * Fixed indentation
>
> Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-578%2Fdscho%2Fgit-gui--askpass-utf-8-v2
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-578/dscho/git-gui--askpass-utf-8-v2
> Pull-Request: https://github.com/gitgitgadget/git/pull/578
>
> Range-diff vs v1:
>
>  1:  3beec773772 ! 1:  7891941486d git-gui--askpass: coerce answers to UTF-8 on Windows
>      @@ -20,6 +20,7 @@
>           This fixes https://github.com/git-for-windows/git/issues/2215
>       
>           Signed-off-by: Luke Bonanomi <lbonanomi@gmail.com>
>      +    Helped-by: Junio C Hamano <gitster@pobox.com>
>           Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
>       
>        diff --git a/git-gui--askpass b/git-gui--askpass
>      @@ -30,7 +31,7 @@
>        	}
>        
>       +	# On Windows, force the encoding to UTF-8: it is what `git.exe` expects
>      -+		if {$::tcl_platform(platform) eq {windows}} {
>      ++	if {$::tcl_platform(platform) eq {windows}} {
>       +		set ::answer [encoding convertto utf-8 $::answer]
>       +	}
>       +
>
>
>  git-gui--askpass | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/git-gui--askpass b/git-gui--askpass
> index 4277f30c411..1c99ee8ca20 100755
> --- a/git-gui--askpass
> +++ b/git-gui--askpass
> @@ -56,6 +56,11 @@ proc finish {} {
>  		}
>  	}
>  
> +	# On Windows, force the encoding to UTF-8: it is what `git.exe` expects
> +	if {$::tcl_platform(platform) eq {windows}} {
> +		set ::answer [encoding convertto utf-8 $::answer]
> +	}
> +
>  	puts $::answer
>  	set ::rc 0
>  }
>
> base-commit: 63a58457e094c9c9bbf562b872009d32f1f88133

> From: Luke Bonanomi <lbonanomi@gmail.com>
> 
> This addresses the issue where Git for Windows asks the user for a
> password, no credential helper is available, and then Git fails to pick
> up non-ASCII characters from the Git GUI helper.
> 
> This can be verified e.g. via
> 
> 	echo host=http://abc.com |
> 	git -c credential.helper= credential fill
> 
> and then pasting some umlauts.
> 
> The underlying reason is that Git for Windows tries to communicate using
> the UTF-8 encoding no matter what the actual current code page is. So
> let's indulge Git for Windows and do use that encoding.
> 
> This fixes https://github.com/git-for-windows/git/issues/2215
> 
> Signed-off-by: Luke Bonanomi <lbonanomi@gmail.com>
> Helped-by: Junio C Hamano <gitster@pobox.com>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>