diff --git a/src/backends/empty/factory.cpp b/src/backends/empty/factory.cpp
index 6de2e34..46dabf5 100644
--- a/src/backends/empty/factory.cpp
+++ b/src/backends/empty/factory.cpp
@@ -7,6 +7,7 @@
 
 #define SOCI_EMPTY_SOURCE
 #include "soci-empty.h"
+#include "backend-loader.h"
 
 #ifdef _MSC_VER
 #pragma warning(disable:4355)
diff --git a/src/backends/mysql/factory.cpp b/src/backends/mysql/factory.cpp
index 638b0d9..23d91bf 100644
--- a/src/backends/mysql/factory.cpp
+++ b/src/backends/mysql/factory.cpp
@@ -8,6 +8,7 @@
 
 #define SOCI_MYSQL_SOURCE
 #include "soci-mysql.h"
+#include "backend-loader.h"
 #include <ciso646>
 
 #ifdef _MSC_VER
diff --git a/src/backends/odbc/factory.cpp b/src/backends/odbc/factory.cpp
index b219d9e..2ca3a5b 100644
--- a/src/backends/odbc/factory.cpp
+++ b/src/backends/odbc/factory.cpp
@@ -7,6 +7,7 @@
 
 #define SOCI_ODBC_SOURCE
 #include "soci-odbc.h"
+#include "backend-loader.h"
 
 using namespace soci;
 using namespace soci::details;
diff --git a/src/backends/sqlite3/factory.cpp b/src/backends/sqlite3/factory.cpp
index ae3d683..a0060bc 100644
--- a/src/backends/sqlite3/factory.cpp
+++ b/src/backends/sqlite3/factory.cpp
@@ -7,6 +7,7 @@
 
 #define SOCI_SQLITE3_SOURCE
 #include "soci-sqlite3.h"
+#include "backend-loader.h"
 
 #ifdef _MSC_VER
 #pragma warning(disable:4355)