Fix cross compile with autotools on windows platform

[star-hengxing]

xmake-io/xmake-repo#6104 windows-arm64

error: D:\a\xmake-repo\xmake-repo\packages\f\ffmpeg\xmake.lua:221: attempt to concatenate a nil value (field 'PATH')
stack traceback:
    [D:\a\xmake-repo\xmake-repo\packages\f\ffmpeg\xmake.lua:221]: in function 'script'
    [...dir\modules\private\action\require\impl\utils\filter.lua:114]: in function 'call'
    [...\modules\private\action\require\impl\actions\install.lua:452]:

  => install ffmpeg 7.0 .. failed