appveyor: we need to run 7zip twice

appveyor.yml

@@ -9,12 +9,13 @@ environment:
  WINDRES: windres
  MINGW_SDK: c:\msys64\mingw32
  SDL2_URL: http://libsdl.org/release/SDL2-devel-2.0.4-mingw.tar.gz
- SDL2_ARCHIVE: SDL2-devel-2.0.4-mingw.tar.gz
+ SDL2_ARCHIVE: SDL2-devel-2.0.4-mingw.tar
  SDL2_MOVE: SDL2-2.0.4\i686-w64-mingw32
 
 install:
-- if not exist "%SDL2_ARCHIVE%" appveyor DownloadFile "%SDL2_URL%" -FileName "%SDL2_ARCHIVE%"
-- 7z x -y "%SDL2_ARCHIVE%" -o%TMP% >null
+- if not exist "%SDL2_ARCHIVE%.gz" appveyor DownloadFile "%SDL2_URL%" -FileName "%SDL2_ARCHIVE%.gz"
+- 7z x -y "%SDL2_ARCHIVE%,gz" -o%TMP% >null
+- 7z x -y "%TMP%\%SDL2_ARCHIVE%" -o%TMP% >null
 - robocopy /S %TMP%\%SDL2_MOVE% %MINGW_SDK%
 - ps: (Get-Content %TMP%\%SDL2_MOVE%\bin\sdl2-config) | ForEach-Object { $_ -replace "/usr/local/cross-tools/i686-w64-mingw32", "%MINGW_SDK%" } | Set-Content %MINGW_SDK%\bin\sdl2-config
 - ps: (Get-Content %TMP%\%SDL2_MOVE%\lib\cmake\SDL2\sdl2-config.cmake) | ForEach-Object { $_ -replace "/usr/local/cross-tools/i686-w64-mingw32", "%MINGW_SDK%" } | Set-Content %MINGW_SDK%\lib\cmake\SDL2\sdl2-config.cmake