diff --git a/CHANGES b/CHANGES
index 7398351954..d3a2e36480 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+5253.	[port]		Support platforms that don't define ULLONG_MAX.
+			[GL #1098]
+
 	--- 9.11.8 released ---
 
 5244.	[security]	Fixed a race condition in dns_dispatch_getnext()
diff --git a/lib/dns/gen.c b/lib/dns/gen.c
index bc419575be..8fd3058e1c 100644
--- a/lib/dns/gen.c
+++ b/lib/dns/gen.c
@@ -43,6 +43,10 @@
 #include "gen-unix.h"
 #endif
 
+#ifndef ULLONG_MAX
+#define ULLONG_MAX (~0ULL)
+#endif
+
 #define INSIST(cond) \
 	if (!(cond)) { \
 		fprintf(stderr, "%s:%d: INSIST(%s)\n", \