Index: deps/v8/include/v8config.h
--- deps/v8/include/v8config.h.orig
+++ deps/v8/include/v8config.h
@@ -184,6 +184,8 @@ path. Add it with -I<path> to the command line
   && !defined(V8_TARGET_OS_FUCHSIA) \
   && !defined(V8_TARGET_OS_IOS) \
   && !defined(V8_TARGET_OS_LINUX) \
+  && !defined(V8_TARGET_OS_OPENBSD) \
+  && !defined(V8_TARGET_OS_FREEBSD) \
   && !defined(V8_TARGET_OS_MACOS) \
   && !defined(V8_TARGET_OS_WIN) \
   && !defined(V8_TARGET_OS_CHROMEOS)
@@ -196,6 +198,8 @@ path. Add it with -I<path> to the command line
   || defined(V8_TARGET_OS_FUCHSIA) \
   || defined(V8_TARGET_OS_IOS) \
   || defined(V8_TARGET_OS_LINUX) \
+  || defined(V8_TARGET_OS_OPENBSD) \
+  || defined(V8_TARGET_OS_FREEBSD) \
   || defined(V8_TARGET_OS_MACOS) \
   || defined(V8_TARGET_OS_WIN) \
   || defined(V8_TARGET_OS_CHROMEOS)
@@ -217,6 +221,16 @@ path. Add it with -I<path> to the command line
 
 #ifdef V8_OS_LINUX
 # define V8_TARGET_OS_LINUX
+#endif
+
+#ifdef V8_OS_OPENBSD
+# define V8_TARGET_OS_OPENBSD
+# define V8_TARGET_OS_BSD
+#endif
+
+#ifdef V8_OS_FREEBSD
+# define V8_TARGET_OS_OPENBSD
+# define V8_TARGET_OS_BSD
 #endif
 
 #ifdef V8_OS_MACOS
