Glob: Append warning message only if destination is non-null

Fix the change from !187 (merged) to not append to nullptr messages.

added 1 commit

• e093a985 - Glob: Append warning message only if destination is non-null

Compare with previous version

Do: merge

merged

mentioned in commit 897d2cb1

mentioned in merge request !187 (merged)

mentioned in merge request cmake/cmake!4758 (merged)