Suppress "unused-const-variable" Clang warnings.

BUILD.gn

Index: BUILD.gn
diff --git a/BUILD.gn b/BUILD.gn
index 3083ca212a647b2aff75cc44bddcb0973a1e088e..19e2520c89f3dd2a9d2c3faee14408245b6ebadd 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -72,7 +72,12 @@ config("icu_code") {
       "-Wno-tautological-compare",
       "-Wno-switch",
       "-Wno-parentheses",
-      ]
+      # ICU generally has no unused variables, but there are a few places where
+      # this warning triggers.
+      # See https://codereview.chromium.org/1222643002/ and
+      # http://www.icu-project.org/trac/ticket/11759.
+      "-Wno-unused-const-variable",
+    ]
     if (is_win) {
       cflags += [
         # See http://bugs.icu-project.org/trac/ticket/11122
@@ -493,6 +498,7 @@ component("icuuc") {
     "//build/config/compiler:rtti",
     "//build/config/compiler:no_chromium_code",
   ]
+  configs += [ ":icu_code" ]

[Peter Mayo, 2015/07/06 18:01:56]

Is this an accident?  It fails my gen rebuild.

[Nico, 2015/07/06 18:03:31]

Yes, that looks like an accident (the same is added again the line below).

[Matt Giuca, 2015/07/07 03:15:53]

Oh no, looks like a rebase accident (wasn't a problem in PS1).

Looks like Nico has already fixed this in c81a1a3. Thanks, Nico.

 
   configs += [ ":icu_code" ]
   public_configs = [ ":icu_config" ]