linux: pass --as-needed to linker

build/common.gypi

 # Copyright (c) 2010 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   'variables': {
     # .gyp files or targets should set chromium_code to 1 if they build
@@ skipping 933 matching lines @@
               '-fno-ident',
               # Put data and code in their own sections, so that unused symbols
               # can be removed at link time with --gc-sections.
               '-fdata-sections',
               '-ffunction-sections',
             ],
             'ldflags': [
               # Specifically tell the linker to perform optimizations.
               # See http://lwn.net/Articles/192624/ .
               '-Wl,-O1',
+              '-Wl,--as-needed',
             ],
             'conditions' : [
               ['no_gc_sections==0', {
                 'ldflags': [
                   '-Wl,--gc-sections',
                 ],
               }],
             ]
           },
         },
@@ skipping 472 matching lines @@
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }
 
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