diff --git a/devel/mrc/files/patch-src_mrc.cpp b/devel/mrc/files/patch-src_mrc.cpp
new file mode 100644
index 000000000000..da9f102d5802
--- /dev/null
+++ b/devel/mrc/files/patch-src_mrc.cpp
@@ -0,0 +1,12 @@
+-- https://github.com/mhekkel/mrc/issues/18
+
+--- src/mrc.cpp.orig	2026-03-22 04:35:33 UTC
++++ src/mrc.cpp
+@@ -47,6 +47,7 @@
+ #include <fcntl.h>
+ #include <sys/stat.h>
+ #include <sys/types.h>
++#include <unistd.h>
+ 
+ #include <mcfp/mcfp.hpp>
+