[build] Conditionally print to stdout on Android

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index b737883542b372d4cf7e2b7aa95f6fc45b1483d3..9539c5d9d8d56f5444c0f3def439927f64c1cef9 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -83,6 +83,7 @@ if (v8_enable_gdbjit == "") {
   }
 }
 
+v8_standalone = defined(v8_standalone_build) && v8_standalone_build
 v8_generated_peephole_source = "$target_gen_dir/bytecode-peephole-table.cc"
 v8_random_seed = "314159265"
 v8_toolset_for_shell = "host"
@@ -329,6 +330,12 @@ config("toolchain") {
   } else if (dcheck_always_on) {
     defines += [ "DEBUG" ]
   }
+
+  if (v8_standalone) {
+    if (is_android) {
+      defines += [ "V8_ANDROID_LOG_STDOUT" ]

[Michael Achenbach, 2016/07/26 15:06:34]

Porting
https://cs.chromium.org/chromium/src/v8/gypfiles/standalone.gypi?q=%22ANDROID...

See differences here:
https://build.chromium.org/p/client.v8.ports/builders/V8%20Android%20Arm%20-%...

The ANDROID define seems to come from chromium now, except for mksnapshot.cc

[vogelheim, 2016/07/27 07:43:40]

Are there any sort of asserts or unit tests for BUILD.gn files?

If this was in regular v8 code, this sort of built-in assumption that elsewhere
surely a flag had already been set and somewhere else entirely we intend rely on
its presence would make me super nervous, and I'd demand a rewrite or at least a
shitload of asserts. Does gn even give us the means to do that?

+    }
+  }
 }
 
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