Fix build error setting --enable-auto-import flag only for MINGW
Fix build error setting --enable-auto-import flag only for MINGW

jcfr/python-cmake-buildsystem,davidsansome/python-cmake-buildsystem,chuckatkins/python-cmake-buildsystem,thewtex/python-cmake-buildsystem,adrianbroher/python-cmake-buildsystem,thewtex/python-cmake-buildsystem,python-cmake-buildsystem/python-cmake-buildsystem,msmolens/python-cmake-buildsystem