diff --git a/Makefile.am b/Makefile.am
index fb15f87b..e73c988b 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -17,7 +17,8 @@
 
 ACLOCAL_AMFLAGS = -I m4 ${ACLOCAL_FLAGS}
 AM_CPPFLAGS = -DDATADIR='"$(datadir)"' -DLIBEXECDIR='"$(libexecdir)"' \
-	-DGLIB_VERSION_MIN_REQUIRED=GLIB_VERSION_2_34 -DGLIB_VERSION_MAX_ALLOWED=GLIB_VERSION_2_34
+	-DGLIB_VERSION_MIN_REQUIRED=GLIB_VERSION_2_34 -DGLIB_VERSION_MAX_ALLOWED=GLIB_VERSION_2_34 \
+	-DSOUP_VERSION_MIN_REQUIRED=SOUP_VERSION_2_40 -DSOUP_VERSION_MAX_ALLOWED=SOUP_VERSION_40
 AM_CFLAGS = $(WARN_CFLAGS)
 
 if BUILD_EMBEDDED_DEPENDENCIES