diff --git a/devel/libcyaml/Portfile b/devel/libcyaml/Portfile
index e2d05071f39b4..09f81f35a3e6c 100644
--- a/devel/libcyaml/Portfile
+++ b/devel/libcyaml/Portfile
@@ -26,6 +26,9 @@ checksums           rmd160  b3ed61d7d628188055fc5a7927171605d236f581 \
                     sha256  8dbd216e1fce90f9f7cca341e5178710adc76ee360a7793ef867edb28f3e4130 \
                     size    86791
 
+# https://github.com/tlsa/libcyaml/pull/231
+patchfiles-append   0001-data.h-use-_Static_assert-when-static_assert-undefin.patch
+
 compiler.c_standard 2011
 
 depends_lib-append  port:libyaml
diff --git a/devel/libcyaml/files/0001-data.h-use-_Static_assert-when-static_assert-undefin.patch b/devel/libcyaml/files/0001-data.h-use-_Static_assert-when-static_assert-undefin.patch
new file mode 100644
index 0000000000000..e65991e966086
--- /dev/null
+++ b/devel/libcyaml/files/0001-data.h-use-_Static_assert-when-static_assert-undefin.patch
@@ -0,0 +1,28 @@
+From 2a5f98ed1d4d8e8b8c6c1850c5cbbe29dff08c94 Mon Sep 17 00:00:00 2001
+From: barracuda156 <vital.had@gmail.com>
+Date: Wed, 22 May 2024 14:43:57 +0800
+Subject: [PATCH] data.h: use _Static_assert when static_assert undefined
+
+Fixes: https://github.com/tlsa/libcyaml/issues/230
+---
+ src/data.h | 7 +++++++
+ 1 file changed, 7 insertions(+)
+
+diff --git src/data.h src/data.h
+index 8b76a9c..4a00e4f 100644
+--- src/data.h
++++ src/data.h
+@@ -12,6 +12,13 @@
+ #ifndef CYAML_DATA_H
+ #define CYAML_DATA_H
+ 
++#include <assert.h>
++#if !defined(static_assert) && (defined(__GNUC__) || defined(__clang__)) \
++	&& defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L \
++	&& __STDC_VERSION__ <= 201710L
++#define static_assert _Static_assert
++#endif
++
+ #include "cyaml/cyaml.h"
+ #include "util.h"
+