--- a/config.h.in
+++ b/config.h.in
@@ -604,3 +604,6 @@
 #define glthread_once_call            libintl_once_call
 #define glthread_once_singlethreaded  libintl_once_singlethreaded
 
+#if HAVE_ALLOCA_H
+#include <alloca.h>
+#endif
--- a/example/medit.c
+++ b/example/medit.c
@@ -119,6 +119,7 @@
 #include <X11/Xaw/SmeBSB.h>
 #include <X11/Xaw/SmeLine.h>
 #include <X11/Xaw/MenuButton.h>
+#include <alloca.h>
 
 /* Global variables.  */