--- build/config/BUILDCONFIG.gn.orig	2018-12-12 22:56:02.000000000 +0100
+++ build/config/BUILDCONFIG.gn	2018-12-15 22:33:58.610110000 +0100
@@ -131,10 +131,10 @@
   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 == "bsd"
 
   # Set to true when compiling with the Clang compiler.
-  is_clang = current_os != "linux" ||
+  is_clang = current_os != "linux" || current_os == "bsd" ||
              (current_cpu != "s390x" && current_cpu != "s390" &&
               current_cpu != "ppc64" && current_cpu != "ppc" &&
               current_cpu != "mips" && current_cpu != "mips64")
@@ -186,8 +186,8 @@
   # 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 == "bsd") {
+    if (target_os != "linux" || target_os != "bsd") {
       # TODO(dpranke) - is_clang normally applies only to the target
       # build, and there is no way to indicate that you want to override
       # it for both the target build *and* the host build. Do we need to
@@ -227,7 +227,7 @@
   assert(host_os == "linux" || host_os == "mac",
          "Android builds are only supported on Linux and Mac hosts.")
   _default_toolchain = "//build/toolchain/android:android_clang_$target_cpu"
-} else if (target_os == "chromeos" || target_os == "linux") {
+} else if (target_os == "chromeos" || target_os == "linux" || target_os == "bsd") {
   # See comments in build/toolchain/cros/BUILD.gn about board compiles.
   if (is_clang) {
     _default_toolchain = "//build/toolchain/linux:clang_$target_cpu"
@@ -301,6 +301,7 @@
   is_nacl = false
   is_posix = false
   is_win = true
+  is_bsd = false
 } else if (current_os == "mac") {
   is_aix = false
   is_android = false
@@ -312,6 +313,7 @@
   is_nacl = false
   is_posix = true
   is_win = false
+  is_bsd = false
 } else if (current_os == "android") {
   is_aix = false
   is_android = true
@@ -323,6 +325,7 @@
   is_nacl = false
   is_posix = true
   is_win = false
+  is_bsd = false
 } else if (current_os == "chromeos") {
   is_aix = false
   is_android = false
@@ -334,6 +337,7 @@
   is_nacl = false
   is_posix = true
   is_win = false
+  is_bsd = false
 } else if (current_os == "nacl") {
   # current_os == "nacl" will be passed by the nacl toolchain definition.
   # It is not set by default or on the command line. We treat is as a
@@ -348,6 +352,7 @@
   is_nacl = true
   is_posix = true
   is_win = false
+  is_bsd = false
 } else if (current_os == "fuchsia") {
   is_aix = false
   is_android = false
@@ -359,6 +364,7 @@
   is_nacl = false
   is_posix = false
   is_win = false
+  is_bsd = false
 } else if (current_os == "ios") {
   is_aix = false
   is_android = false
@@ -370,6 +376,7 @@
   is_nacl = false
   is_posix = true
   is_win = false
+  is_bsd = false
 } else if (current_os == "linux") {
   is_aix = false
   is_android = false
@@ -381,6 +388,7 @@
   is_nacl = false
   is_posix = true
   is_win = false
+  is_bsd = false
 } else if (current_os == "aix") {
   is_aix = true
   is_android = false
@@ -392,6 +400,19 @@
   is_nacl = false
   is_posix = true
   is_win = false
+  is_bsd = false
+} else if (current_os == "bsd") {
+  is_aix = false
+  is_android = false
+  is_chromeos = false
+  is_fuchsia = false
+  is_ios = false
+  is_linux = true
+  is_mac = false
+  is_nacl = false
+  is_posix = true
+  is_win = false
+  is_bsd = true
 }
 
 # =============================================================================