Trickery to handle unset @BUILD_FLAVOR@

OBS-URL: https://build.opensuse.org/package/show/science:HPC/mvapich2?expand=0&rev=13

mvapich2.spec

@@ -16,8 +16,10 @@
 #
 
 %global flavor @BUILD_FLAVOR@%nil
+%define unset_flavor BUILD_FLAVOR
 
-%if "%{flavor}" == ""
+# Tricker to detect if BUILD_FLAVOR was not replaced and handle it gracefully
+%if "%{flavor}" == "" || "%{flavor}" == "@%{unset_flavor}@"
 %define pack_suff %{nil}
 %else
 %define pack_suff -%{flavor}