Fix compilation with xmlsec 1.3
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This merge request is automatically cherrypicked from !1602 (merged) from source branch https://source.coderefinery.org/ellert/arc/-/tree/xmlsec-1.3 orginally made by @ellert .
The original MR went to branch: https://source.coderefinery.org/nordugrid/arc/-/tree/next
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The update to xmlsec1 1.3 in Fedora rawhide broke the compilation.