base: remove -latomic in CrOS chroot

base/BUILD.gn

Index: base/BUILD.gn
diff --git a/base/BUILD.gn b/base/BUILD.gn
index 78953bef001f4cec586d935a9680e804755f31d3..992e357855a4454dfbc6e07342493cdf598ca7e4 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -1129,7 +1129,14 @@ component("base") {
 
   # Needed for <atomic> if using newer C++ library than sysroot
   if (!use_sysroot && (is_android || (is_linux && !is_chromecast))) {
-    libs = [ "atomic" ]
+    # libatomic is not provided by the CrOS sysroot, so don't attempt
+    # to link to it under these circumstances. is_chromeos = true /
+    # target_os = "chrome_os" are not exclusive to the CrOS sysroot
+    # (since these can be built for desktop Linux too), so check the
+    # toolchain to make sure.
+    if (host_toolchain != "//build/toolchain/cros:host") {

[Dirk Pranke, 2017/04/25 19:18:06]

I'd fold the comment and the check into the outer if condition. Having an if
contain a single additional if reads a little weird.

Otherwise lgtm.

+      libs = [ "atomic" ]
+    }
   }
 
   if (use_experimental_allocator_shim) {