Para openSUSE Tumbleweed execute o seguinte como root:
zypper addrepo https://download.opensuse.org/repositories/isv:ownCloud:toolchains:mingw:win32:2.4-qt59/openSUSE_Tumbleweed/isv:ownCloud:toolchains:mingw:win32:2.4-qt59.repo
zypper refresh
zypper install mingw32-gcc
Para openSUSE Leap 42.3 execute o seguinte como root:
zypper addrepo https://download.opensuse.org/repositories/isv:ownCloud:toolchains:mingw:win32:2.4-qt59/openSUSE_Leap_42.3/isv:ownCloud:toolchains:mingw:win32:2.4-qt59.repo
zypper refresh
zypper install mingw32-gcc