Index: compiler-rt/lib/sanitizer_common/sanitizer_platform.h
--- compiler-rt/lib/sanitizer_common/sanitizer_platform.h.orig
+++ compiler-rt/lib/sanitizer_common/sanitizer_platform.h
@@ -16,7 +16,7 @@
     !defined(__APPLE__) && !defined(_WIN32) && !defined(__Fuchsia__) &&     \
     !(defined(__sun__) && defined(__svr4__)) && !defined(__HAIKU__) &&      \
     !defined(__wasi__) && !defined(__NVPTX__) && !defined(__AMDGPU__) &&    \
-    !defined(__SPIRV__) && !defined(_AIX)
+    !defined(__SPIRV__) && !defined(_AIX) && !defined(__OpenBSD__)
 #  error "This operating system is not supported"
 #endif
 
@@ -57,6 +57,12 @@
 #  define SANITIZER_NETBSD 0
 #endif
 
+#if defined(__OpenBSD__)
+# define SANITIZER_OPENBSD 1
+#else
+# define SANITIZER_OPENBSD 0
+#endif
+
 #if defined(__sun__) && defined(__svr4__)
 #  define SANITIZER_SOLARIS 1
 #else
@@ -156,9 +162,10 @@
 #  define SANITIZER_MUSL 0
 #endif
 
-#define SANITIZER_POSIX                                       \
-  (SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_APPLE || \
-   SANITIZER_NETBSD || SANITIZER_SOLARIS || SANITIZER_HAIKU || SANITIZER_AIX)
+#define SANITIZER_POSIX                                        \
+  (SANITIZER_FREEBSD || SANITIZER_LINUX || SANITIZER_APPLE ||  \
+   SANITIZER_NETBSD || SANITIZER_SOLARIS || SANITIZER_HAIKU || \
+   SANITIZER_AIX || SANITIZER_OPENBSD)
 
 #if __LP64__ || defined(_WIN64)
 #  define SANITIZER_WORDSIZE 64
