Add default build with linux device layer (project-chip#1568)

* Add default build with linux device layer

* Rename linux_embedded to linux_x64_gcc_embedded for consistency

BUILD.gn

@@ -106,8 +106,11 @@ if (current_toolchain != "${dir_pw_toolchain}/dummy:dummy") {
     # Enable building chip with gcc.
     enable_host_gcc_build = enable_default_builds
 
-    # Build building chip with gcc & mbedtls.
-    enable_host_gcc_mbdtls_build = enable_default_builds
+    # Enable building chip with gcc & mbedtls.
+    enable_host_gcc_mbedtls_build = enable_default_builds
+
+    # Enable building chip for linux embedded.
+    enable_linux_embedded_build = enable_default_builds && host_os == "linux"
 
     # Build the chip-tool example.
     enable_standalone_chip_tool_build = enable_default_builds
@@ -134,6 +137,13 @@ if (current_toolchain != "${dir_pw_toolchain}/dummy:dummy") {
     toolchain = "${chip_root}/config/mbedtls/toolchain:${host_os}_${host_cpu}_gcc_mbedtls"
   }
 
+  if (host_os == "linux") {
+    chip_build("linux_embedded") {
+      toolchain =
+          "${chip_root}/config/linux/toolchain:linux_${host_cpu}_gcc_embedded"
+    }
+  }
+
   standalone_toolchain = "${chip_root}/config/standalone/toolchain:standalone"
 
   group("standalone_chip_tool") {
@@ -164,9 +174,12 @@ if (current_toolchain != "${dir_pw_toolchain}/dummy:dummy") {
     if (enable_host_gcc_build) {
       deps += [ ":all_host_gcc" ]
     }
-    if (enable_host_gcc_mbdtls_build) {
+    if (enable_host_gcc_mbedtls_build) {
       deps += [ ":all_host_gcc_mbedtls" ]
     }
+    if (enable_linux_embedded_build) {
+      deps += [ ":all_linux_embedded" ]
+    }
     if (enable_standalone_chip_tool_build) {
       deps += [ ":standalone_chip_tool" ]
     }
@@ -190,9 +203,12 @@ if (current_toolchain != "${dir_pw_toolchain}/dummy:dummy") {
       if (enable_host_gcc_build) {
         deps += [ ":check_host_gcc" ]
       }
-      if (enable_host_gcc_mbdtls_build) {
+      if (enable_host_gcc_mbedtls_build) {
         deps += [ ":check_host_gcc_mbedtls" ]
       }
+      if (enable_linux_embedded_build) {
+        deps += [ ":check_linux_embedded" ]
+      }
     }
   }
 }

config/linux/toolchain/BUILD.gn

@@ -0,0 +1,26 @@
+# Copyright (c) 2020 Project CHIP Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import("//build_overrides/chip.gni")
+
+import("//build/toolchain/gcc_toolchain.gni")
+
+gcc_toolchain("linux_${host_cpu}_gcc_embedded") {
+  toolchain_args = {
+    current_os = "linux"
+    current_cpu = host_cpu
+    is_clang = false
+    import("${chip_root}/src/platform/Linux/args.gni")
+  }
+}