Replaced a lambda by an explicit functor for compatibility issues

src/field/DistributedField.cpp

@@ -196,6 +196,18 @@ namespace gmshfem::field
 
     common::Timer timeComm;
     timeComm.tick();
+
+    // Not a lambda because of an OpenMP issue on MacOS.
+    struct KeyFinder {
+      const DofGlobalIndex key;
+      KeyFinder(const DofGlobalIndex &key) :
+        key(key) {}
+      bool operator()(const dofs::Dof *dof) const
+      {
+        return dof->numType() == key.first && dof->entity() == key.second;
+      }
+    };
+
     for(auto &[key, value] : ownershipData) {
 
       if(std::find(value.readers.begin(), value.readers.end(), rank) != value.readers.end()) {
@@ -204,7 +216,7 @@ namespace gmshfem::field
         msg::debug << "[" << rank << "] reads from overlap " << key.first << ',' << key.second << msg::endl;
       }
       else if(value.writers.empty()) {
-        if(std::find_if(_innerDofs.begin(), _innerDofs.end(), [key](dofs::Dof *dof) { return dof->numType() == key.first && dof->entity() == key.second; }) != _innerDofs.end()) {
+        if(std::find_if(_innerDofs.begin(), _innerDofs.end(), KeyFinder(key)) != _innerDofs.end()) {
           // No one is writing it on the overlap, but it's my inner DOF, so I own it
           _toSendID.insert(key);
           ++innerDofToSend;