Squash commits for public release

BUILD.gn

@@ -0,0 +1,25 @@
+group("build") {
+  deps = [
+    ":env",
+    "//build/boot:boot",
+    "//build/kernel:kernel",
+
+    "//build/libs:libs",
+    "//build/third_party:third_party",
+    "//build/userland:userland",
+  ]
+  if (compile_tests) {
+    deps += [ "//build/test:test" ]
+  }
+}
+
+group("env") {
+  deps = [
+    ":scripts",
+    "//build/tools:prepare_env",
+  ]
+}
+
+group("scripts") {
+  deps = [ "//build/tools:build_scripts" ]
+}