Add mac hermetic support to build/config/mac/sdk_info.py.

build/toolchain/mac/BUILD.gn

Index: build/toolchain/mac/BUILD.gn
diff --git a/build/toolchain/mac/BUILD.gn b/build/toolchain/mac/BUILD.gn
index 5ccda9a9bc0238eba7c6f79d233f622ef76d5fe7..e08b7dff9ac48599e6aee8248aee7c883dd00abd 100644
--- a/build/toolchain/mac/BUILD.gn
+++ b/build/toolchain/mac/BUILD.gn
@@ -8,7 +8,9 @@
 
 import("../goma.gni")
 import("//build/config/clang/clang.gni")
-import("//build/config/ios/ios_sdk.gni")
+if (is_ios) {
+  import("//build/config/ios/ios_sdk.gni")
+}
 import("//build/config/mac/mac_sdk.gni")
 import("//build/config/mac/symbols.gni")
 
@@ -400,22 +402,24 @@ mac_toolchain("clang_x64") {
   toolchain_os = "mac"
 }
 
-mac_toolchain("ios_clang_arm") {
-  toolchain_cpu = "arm"
-  toolchain_os = "ios"
-}
+if (is_ios) {

[sdefresne, 2016/07/28 17:36:31]

I don't think this is necessary, instead you could do the following at the top
of the file which should work:

if (is_ios) {
  import("//build/config/ios/ios_sdk.gni")
} else {
  additional_toolchains = []
}

[justincohen, 2016/07/28 17:59:40]

Generating files...
ERROR at //build/toolchain/mac/BUILD.gn:14:27: Assignment had no effect.
  additional_toolchains = []
                          ^
You set the variable "additional_toolchains" here and it was unused before it
went
out of scope.
See //BUILD.gn:65:1: which caused the file to be included.
group("gn_all") {
^----------------

[Dirk Pranke, 2016/07/28 19:07:20]

That, plus it's probably better hygiene to not declare these targets on non-ios
builds.

+  mac_toolchain("ios_clang_arm") {
+    toolchain_cpu = "arm"
+    toolchain_os = "ios"
+  }
 
-mac_toolchain("ios_clang_arm64") {
-  toolchain_cpu = "arm64"
-  toolchain_os = "ios"
-}
+  mac_toolchain("ios_clang_arm64") {
+    toolchain_cpu = "arm64"
+    toolchain_os = "ios"
+  }
 
-mac_toolchain("ios_clang_x86") {
-  toolchain_cpu = "x86"
-  toolchain_os = "ios"
-}
+  mac_toolchain("ios_clang_x86") {
+    toolchain_cpu = "x86"
+    toolchain_os = "ios"
+  }
 
-mac_toolchain("ios_clang_x64") {
-  toolchain_cpu = "x64"
-  toolchain_os = "ios"
+  mac_toolchain("ios_clang_x64") {
+    toolchain_cpu = "x64"
+    toolchain_os = "ios"
+  }
 }