[iOS/OSX/GN] Add -install_name to the shared_library ldflags on iOS.

build/config/ios/rules.gni

 # 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/ios/ios_sdk.gni")
 import("//build/config/mac/rules.gni")
 
 # TODO(crbug.com/297668): refactor this template to extract common behaviour
 # between OS X and iOS bundle generation, then create a generic "app" template
 # that forward to "executable" on all platform except iOS/OS X.
@@ skipping 308 matching lines @@
       sources = _public_headers
       outputs = [
         "$_framework_root/Headers/{{source_file_part}}",
       ]
     }
 
     _headers_map_config = _target_name + "_headers_map"
     config(_headers_map_config) {
       visibility = [ ":$_target_name" ]
       include_dirs = [ _header_map_filename ]
+      ldflags = [
+        "-install_name",
+        "@rpath/$_framework_name/$_output_name",
+      ]
     }
 
     _framework_public_config = _target_name + "_public_config"
     config(_framework_public_config) {
       # TODO(sdefresne): should we have a framework_dirs similar to lib_dirs
       # and include_dirs to avoid duplicate values on the command-line.
       common_flags = [ "-F" + rebase_path("$root_out_dir/.", root_out_dir) ]
       cflags_objc = common_flags
       cflags_objcc = common_flags
       ldflags = common_flags
@@ skipping 45 matching lines @@
       deps = [
         ":$_framework_target",
       ]
       if (!defined(public_configs)) {
         public_configs = []
       }
       public_configs += [ ":$_framework_public_config" ]
     }
   }
 }