[Chromecast] Make static_config a noop for clang builds

build/config/chromecast/BUILD.gn

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/chromecast_build.gni")
 
 assert(is_chromecast)
 
 config("static_config") {
-  ldflags = [
-    # Don't allow visible symbols from libraries that contain
-    # assembly code with symbols that aren't hidden properly.
-    # http://b/26390825
-    "-Wl,--exclude-libs=libffmpeg.a",
-  ]
+  if (!is_clang) {
+    ldflags = [
+      # Don't allow visible symbols from libraries that contain
+      # assembly code with symbols that aren't hidden properly.
+      # http://b/26390825
+      "-Wl,--exclude-libs=libffmpeg.a",
+    ]

[gfhuang, 2017/04/11 17:54:27]

is this safe to remove?

[wzhong, 2017/04/11 17:57:41]

No. Still needed for GCC build.

 
-  if (!is_android) {
-    ldflags += [
-      # We want to statically link libstdc++/libgcc on Linux.
-      # (On Android, libstdc++ and libgcc aren't used.)
-      "-static-libstdc++",
-      "-static-libgcc",
-    ]
+    if (!is_android) {
+      ldflags += [
+        # We want to statically link libstdc++/libgcc on Linux.
+        # (On Android, libstdc++ and libgcc aren't used.)
+        "-static-libstdc++",
+        "-static-libgcc",

[wzhong, 2017/04/11 17:57:41]

What is the implication in practice?

Does clang take those flags?

[bcf, 2017/04/11 18:17:07]

Yes, clang will take the flags.

In practice this means clang builds will use shared libc++, statically link
libgcc, and statically link libstdc++. Since we're using libc++, statically
linking libstdc++ probably won't actually bring in anything.

+      ]
+    }
   }
 }
 
 config("ldconfig") {
   visibility = [ ":*" ]
 
   # Chromecast executables depend on several shared libraries in
   # /oem_cast_shlib, $ORIGIN, and $ORIGIN/lib. Add these rpaths to each binary.
   # This is explicitly disabled in Chrome for security reasons (see comments in
   # //build/config/gcc/BUILD.gn), but necessary on Chromecast so that OEM's may
@@ skipping 34 matching lines @@
 
     # Despite including libstdc++/libgcc archives, we still need to specify
     # static linking for them in order to prevent the executable from having a
     # dynamic dependency on them.
     configs += [ ":static_config" ]
   }
 }
 
 config("shared_library_config") {
   configs = [ ":ldconfig" ]
-  if (!is_clang && current_cpu == "arm") {
+  if (current_cpu == "arm") {
     configs += [ ":static_config" ]
   }
 }