Drop C++17 if init-statements to support older compilers.

diff --git a/src/insets/InsetIndex.cpp b/src/insets/InsetIndex.cpp
index d72527a2126f318edf79f454d277254281071b8e..54757a7a978907012f61e41f69cda213da7967f7 100644 (file)
--- a/src/insets/InsetIndex.cpp
+++ b/src/insets/InsetIndex.cpp
@@ -373,7 +373,8 @@ void InsetIndex::docbook(XMLStream & xs, OutputParams const & runparams) const
 
        // Handle primary, secondary, and tertiary terms (entries, subentries, and subsubentries, for LaTeX).
        vector<docstring> terms;
-       if (const vector<docstring> potential_terms = getSubentriesAsText(runparams); !potential_terms.empty()) {
+       const vector<docstring> potential_terms = getSubentriesAsText(runparams);
+       if (!potential_terms.empty()) {
                terms = potential_terms;
                // The main term is not present in the vector, as it's not a subentry. The main index term is inserted raw in
                // the index inset. Considering that the user either uses the new or the legacy mechanism, the main term is the