add--interactive: fix external command invocation on Windows
Back in
21e9757e (Hack git-add--interactive to make it work with
ActiveState Perl, 2007-08-01), the invocation of external commands was
changed to use qx{} on Windows. The rationale was that the command
interpreter on Windows is not a POSIX shell, but rather Windows's CMD.
That patch was wrong to include 'msys' in the check whether to use qx{}
or not: 'msys' identifies MSYS perl as shipped with Git for Windows,
which does not need the special treatment; qx{} should be used only with
ActiveState perl, which is identified by 'MSWin32'.
Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>