Fix compilation and execution of IfcConvert

src/ifcparse/IfcSchema.cpp

@@ -60,7 +60,14 @@ IfcParse::schema_definition::~schema_definition() {
 	}
 }
 
+#include "../ifcparse/Ifc2x3.h"
+#include "../ifcparse/Ifc4.h"
+
 const IfcParse::schema_definition* IfcParse::schema_by_name(const std::string& name) {
+	// TODO: initialize automatically somehow
+	Ifc2x3::get_schema();
+	Ifc4::get_schema();
+
 	std::map<std::string, const IfcParse::schema_definition*>::const_iterator it = schemas.find(name);
 	if (it == schemas.end()) {
 		throw IfcParse::IfcException("No schema named " + name);