Merge branch '364-modbuild-if-no-variant-is-specified-an-uset-variable-is-used' into 'master'
Resolve "modbuild: if no variant is specified, an uset variable is used"
Closes #364 (closed)
See merge request !375 (merged)
(cherry picked from commit 6603d915)
8ceec1a8 build-system: using unset variables fixed if no variants specified
Co-authored-by: gsell achim.gsell@psi.ch