GN: Use NaCl's newlib objdump for PNaCl

build/config/nacl/rules.gni

Index: build/config/nacl/rules.gni
diff --git a/build/config/nacl/rules.gni b/build/config/nacl/rules.gni
index adecc305b7f81fd478dd6fa3074f7d2b7bc48141..c298aabb5624f0b28314c7980eb6c63f1c8560af 100644
--- a/build/config/nacl/rules.gni
+++ b/build/config/nacl/rules.gni
@@ -36,7 +36,14 @@ template("generate_nmf") {
                              "testonly",
                            ])
 
-    objdump = rebase_path("${nacl_toolprefix}objdump")
+    # TODO(phosek): Remove this conditional once
+    # https://bugs.chromium.org/p/nativeclient/issues/detail?id=4339 is
+    # resolved.
+    if (current_cpu == "pnacl") {
+      objdump = rebase_path("${nacl_toolchain_bindir}/x86_64-nacl-objdump")
+    } else {
+      objdump = rebase_path("${nacl_toolprefix}objdump")
+    }
     if (host_os == "win") {
       objdump += ".exe"
     }