From 46e52fdae08b89264a0b23f94391c2bf637def34 Mon Sep 17 00:00:00 2001
From: Darren Tucker <dtucker@dtucker.net>
Date: Wed, 16 Apr 2025 22:29:17 +1000
Subject: [PATCH] Provide INFINITY if it's not provided.

INFINITY is specified in c99, so define if not provided.
---
 configure.ac | 5 +++++
 defines.h    | 7 +++++++
 2 files changed, 12 insertions(+)

diff --git a/configure.ac b/configure.ac
index bbddca009..69b74add8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2280,6 +2280,11 @@ AC_CHECK_DECLS([offsetof], , , [
 #include <stddef.h>
 	])
 
+AC_CHECK_DECLS([INFINITY], ,
+    AC_CHECK_DECLS(__builtin_inff),
+    [#include <math.h>]
+)
+
 # extra bits for select(2)
 AC_CHECK_DECLS([howmany, NFDBITS], [], [], [[
 #include <sys/param.h>
diff --git a/defines.h b/defines.h
index d2baeb940..3721ae16e 100644
--- a/defines.h
+++ b/defines.h
@@ -986,4 +986,11 @@ struct winsize {
 /* The ML-KEM768 implementation also uses C89 features */
 # define USE_MLKEM768X25519	1
 #endif
+
+#if defined(HAVE_DECL_INFINITY) && HAVE_DECL_INFINITY == 0
+# if defined(HAVE_DECL___BUILTIN_INFF) && HAVE_DECL___BUILTIN_INFF == 1
+#  define INFINITY __builtin_inff()
+# endif
+#endif
+
 #endif /* _DEFINES_H */
-- 
2.47.3