Important Update as of 2021: is_opensuse ideally notbe used only. To distinguish in between openSUSE Tumbleweed and SUSE Linux Enterprise check the presence of sle_version. openSUSE Leap 15.3+ should have the identical functionality as SUSE Linux Enterprise.
This pull request fixes issue #16 following advice from https://en.opensuse.org/openSUSE:Packaging_for_Leap which states that the macro
is_opensuse
is undefined and also states: