[iOS] Define build/config/ios:ios_dynamic_flags for default linker flags.

build/config/BUILD.gn

 # Copyright (c) 2013 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/allocator.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/chromecast_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/dcheck_always_on.gni")
 import("//build/config/features.gni")
@@ skipping 371 matching lines @@
 config("executable_config") {
   configs = []
 
   if (is_win) {
     configs += _windows_linker_configs
   } else if (is_mac) {
     configs += [
       "//build/config/mac:mac_dynamic_flags",
       "//build/config/mac:mac_executable_flags",
     ]
+  } else if (is_ios) {
+    configs += [ "//build/config/ios:ios_dynamic_flags" ]
   } else if (is_linux || is_android) {
     configs += [ "//build/config/gcc:executable_ldconfig" ]
     if (is_android) {
       configs += [ "//build/config/android:executable_config" ]
     } else if (is_chromecast) {
       configs += [ "//build/config/chromecast:executable_config" ]
     }
   }
 
   # If we're using the prebuilt instrumented libraries with the sanitizers, we
   # need to add ldflags to every binary to make sure they are picked up.
   if (prebuilt_instrumented_libraries_available) {
     configs += [ "//third_party/instrumented_libraries:prebuilt_ldflags" ]
   }
   if (use_locally_built_instrumented_libraries) {
     configs += [ "//third_party/instrumented_libraries:locally_built_ldflags" ]
   }
 }
 
 # Shared library configs -------------------------------------------------------
 
 # This config defines the configs applied to all shared libraries.
 config("shared_library_config") {
   configs = []
 
   if (is_win) {
     configs += _windows_linker_configs
   } else if (is_mac) {
     configs += [ "//build/config/mac:mac_dynamic_flags" ]
+  } else if (is_ios) {
+    configs += [ "//build/config/ios:ios_dynamic_flags" ]
   } else if (is_chromecast) {
     configs += [ "//build/config/chromecast:shared_library_config" ]
   }
 
   # If we're using the prebuilt instrumented libraries with the sanitizers, we
   # need to add ldflags to every binary to make sure they are picked up.
   if (prebuilt_instrumented_libraries_available) {
     configs += [ "//third_party/instrumented_libraries:prebuilt_ldflags" ]
   }
   if (use_locally_built_instrumented_libraries) {
@@ skipping 34 matching lines @@
       # file doesn't exist, no error will be generated (probably MS tested this
       # case but forgot the other one?). To reproduce this error, do a build,
       # then delete the precompile.c.obj file, then build again.
       cflags_c = [ "/wd4206" ]
     } else if (is_mac) {
       precompiled_header = "build/precompile.h"
       precompiled_source = "//build/precompile.h"
     }
   }
 }