Index: v8/BUILD.gn
--- v8/BUILD.gn.orig
+++ v8/BUILD.gn
@@ -1404,6 +1404,14 @@ config("toolchain") {
   } else if (target_os == "chromeos") {
     defines += [ "V8_HAVE_TARGET_OS" ]
     defines += [ "V8_TARGET_OS_CHROMEOS" ]
+  } else if (target_os == "openbsd") {
+    defines += [ "V8_HAVE_TARGET_OS" ]
+    defines += [ "V8_TARGET_OS_OPENBSD" ]
+    defines += [ "V8_TARGET_OS_BSD" ]
+  } else if (target_os == "freebsd") {
+    defines += [ "V8_HAVE_TARGET_OS" ]
+    defines += [ "V8_TARGET_OS_FREEBSD" ]
+    defines += [ "V8_TARGET_OS_BSD" ]
   }
 
   # TODO(infra): Support v8_enable_prof on Windows.
@@ -2331,6 +2339,11 @@ template("run_mksnapshot") {
         "--turbo-log-builtins-count-input",
         v8_log_builtins_block_count_input,
       ]
+      if (v8_current_cpu == "x86") {
+        args -= [
+          "--abort-on-bad-builtin-profile-data",
+        ]
+      }
     }
 
     if (v8_enable_builtins_profiling) {
@@ -6081,7 +6094,7 @@ v8_component("v8_libbase") {
     }
   }
 
-  if (is_linux || is_chromeos) {
+  if ((is_linux || is_chromeos) && !is_bsd) {
     sources += [
       "src/base/debug/stack_trace_posix.cc",
       "src/base/platform/platform-linux.cc",
@@ -6092,6 +6105,18 @@ v8_component("v8_libbase") {
       "dl",
       "rt",
     ]
+  } else if (is_openbsd) {
+    sources += [
+      "src/base/debug/stack_trace_posix.cc",
+      "src/base/platform/platform-openbsd.cc",
+    ]
+    libs = [ "execinfo" ]
+  } else if (is_freebsd) {
+    sources += [
+      "src/base/debug/stack_trace_posix.cc",
+      "src/base/platform/platform-freebsd.cc",
+    ]
+    libs = [ "execinfo" ]
   } else if (current_os == "aix") {
     sources += [
       "src/base/debug/stack_trace_posix.cc",