diff --git a/ActiveSync/SOGoActiveSyncDispatcher.m b/ActiveSync/SOGoActiveSyncDispatcher.m
index 37f68e08f..2ed5d3b53 100644
--- a/ActiveSync/SOGoActiveSyncDispatcher.m
+++ b/ActiveSync/SOGoActiveSyncDispatcher.m
@@ -137,6 +137,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #import <GDLContentStore/GCSChannelManager.h>
 
+#include <signal.h>
 #include <unistd.h>
 
 #ifdef HAVE_OPENSSL