--- citus-9.1.0/src/backend/distributed/shared_library_init.c.1	2019-12-05 08:40:31.298712613 +0000
+++ citus-9.1.0/src/backend/distributed/shared_library_init.c	2019-12-05 08:41:18.885079836 +0000
@@ -12,6 +12,9 @@
 #include <limits.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#ifdef __sun
+#include <alloca.h>
+#endif
 
 #include "fmgr.h"
 #include "miscadmin.h"