vector<Column_x_positions> sol;
message (_ ("Calculating line breaks...") + " ");
int system_count = robust_scm2int (layout ()->c_variable ("system-count"), 0);
if (system_count)
vector<Column_x_positions> sol;
message (_ ("Calculating line breaks...") + " ");
int system_count = robust_scm2int (layout ()->c_variable ("system-count"), 0);
if (system_count)