diff --git a/src/event/ServerSocket.cxx b/src/event/ServerSocket.cxx
index f0b02e34c..342acc04e 100644
--- a/src/event/ServerSocket.cxx
+++ b/src/event/ServerSocket.cxx
@@ -32,6 +32,8 @@
 #include "util/Error.hxx"
 #include "util/Domain.hxx"
 
+#include <glib.h>
+
 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
diff --git a/src/system/SocketError.cxx b/src/system/SocketError.cxx
index d3569c6f1..315a86e1f 100644
--- a/src/system/SocketError.cxx
+++ b/src/system/SocketError.cxx
@@ -21,4 +21,26 @@
 #include "SocketError.hxx"
 #include "util/Domain.hxx"
 
+#include <glib.h>
+
 const Domain socket_domain("socket");
+
+#ifdef WIN32
+
+SocketErrorMessage::SocketErrorMessage(socket_error_t code)
+{
+	DWORD nbytes = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM |
+				     FORMAT_MESSAGE_IGNORE_INSERTS |
+				     FORMAT_MESSAGE_MAX_WIDTH_MASK,
+				     NULL, code, 0,
+				     (LPSTR)msg, sizeof(msg), NULL);
+	if (nbytes == 0)
+		strcpy(msg, "Unknown error");
+}
+
+#else
+
+SocketErrorMessage::SocketErrorMessage(socket_error_t code)
+	:msg(g_strerror(code)) {}
+
+#endif
diff --git a/src/system/SocketError.hxx b/src/system/SocketError.hxx
index c42e267dd..2b8332715 100644
--- a/src/system/SocketError.hxx
+++ b/src/system/SocketError.hxx
@@ -23,8 +23,6 @@
 #include "gcc.h"
 #include "util/Error.hxx"
 
-#include <glib.h>
-
 #ifdef WIN32
 #include <winsock2.h>
 typedef DWORD socket_error_t;
@@ -97,18 +95,9 @@ class SocketErrorMessage {
 
 public:
 #ifdef WIN32
-	explicit SocketErrorMessage(socket_error_t code=GetSocketError()) {
-		DWORD nbytes = FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM |
-					     FORMAT_MESSAGE_IGNORE_INSERTS |
-					     FORMAT_MESSAGE_MAX_WIDTH_MASK,
-					     NULL, code, 0,
-					     (LPSTR)msg, sizeof(msg), NULL);
-		if (nbytes == 0)
-			strcpy(msg, "Unknown error");
-	}
+	explicit SocketErrorMessage(socket_error_t code=GetSocketError());
 #else
-	explicit SocketErrorMessage(socket_error_t code=GetSocketError())
-		:msg(g_strerror(code)) {}
+	explicit SocketErrorMessage(socket_error_t code=GetSocketError());
 #endif
 
 	operator const char *() const {