$NetBSD$

--- build/config/BUILDCONFIG.gn.orig	2020-07-15 18:55:48.000000000 +0000
+++ build/config/BUILDCONFIG.gn
@@ -131,10 +131,10 @@ declare_args() {
   is_official_build = false
 
   # Whether we're a traditional desktop unix.
-  is_desktop_linux = current_os == "linux"
+  is_desktop_linux = current_os == "linux" || current_os == "freebsd" || current_os == "netbsd" || current_os == "openbsd"
 
   # Set to true when compiling with the Clang compiler.
-  is_clang = current_os != "linux" ||
+  is_clang = (current_os != "linux" && current_os != "netbsd") ||
              (current_cpu != "s390x" && current_cpu != "s390" &&
               current_cpu != "ppc64" && current_cpu != "ppc" &&
               current_cpu != "mips" && current_cpu != "mips64")
@@ -186,8 +186,8 @@ if (host_toolchain == "") {
   # TODO(dpranke): Add some sort of assert here that verifies that
   # no toolchain omitted host_toolchain from its toolchain_args().
 
-  if (host_os == "linux") {
-    if (target_os != "linux") {
+  if (host_os == "linux" || host_os == "freebsd" || host_os == "openbsd") {
+    if (target_os != "linux" && target_os != "freebsd" && target_os != "openbsd") {
       host_toolchain = "//build/toolchain/linux:clang_$host_cpu"
     } else if (is_clang) {
       host_toolchain = "//build/toolchain/linux:clang_$host_cpu"
@@ -213,6 +213,8 @@ if (host_toolchain == "") {
     }
   } else if (host_os == "aix") {
     host_toolchain = "//build/toolchain/aix:$host_cpu"
+  } else if (host_os == "netbsd") {
+    host_toolchain = "//build/toolchain/netbsd:$host_cpu"
   } else {
     assert(false, "Unsupported host_os: $host_os")
   }
@@ -224,7 +226,7 @@ if (target_os == "android") {
   assert(host_os == "linux" || host_os == "mac",
          "Android builds are only supported on Linux and Mac hosts.")
   _default_toolchain = "//build/toolchain/android:android_clang_$target_cpu"
-} else if (target_os == "chromeos" || target_os == "linux") {
+} else if (target_os == "chromeos" || target_os == "linux" || target_os == "freebsd" || target_os == "netbsd" || target_os == "openbsd") {
   # See comments in build/toolchain/cros/BUILD.gn about board compiles.
   if (is_clang) {
     _default_toolchain = "//build/toolchain/linux:clang_$target_cpu"
@@ -254,6 +256,8 @@ if (target_os == "android") {
   _default_toolchain = "//build/toolchain/win:uwp_$target_cpu"
 } else if (target_os == "aix") {
   _default_toolchain = "//build/toolchain/aix:$target_cpu"
+} else if (target_os == "netbsd") {
+  _default_toolchain = "//build/toolchain/netbsd:$target_cpu"
 } else {
   assert(false, "Unsupported target_os: $target_os")
 }
@@ -292,6 +296,10 @@ is_linux = current_os == "chromeos" || c
 is_mac = current_os == "mac"
 is_nacl = current_os == "nacl"
 is_win = current_os == "win" || current_os == "winuwp"
+is_bsd = current_os == "freebsd" || current_os == "netbsd" || current_os == "openbsd"
+is_freebsd = current_os == "freebsd"
+is_netbsd = current_os == "netbsd"
+is_openbsd = current_os == "openbsd"
 
 is_posix = !is_win && !is_fuchsia
 
@@ -355,7 +363,7 @@ if (!is_ios) {
 if (!is_mac && !is_ios) {
   sources_assignment_filter += [ "*.mm" ]
 }
-if (!is_linux) {
+if (!is_linux && !is_bsd) {
   sources_assignment_filter += [
     "*_linux.h",
     "*_linux.cc",