GN: get echo-headers sources via exec_script

gyp/icu.gyp

 # Copyright (c) 2012 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.
 
 {
   'includes': [
     'common_variables.gypi',
   ],
   'variables': {
     'component%': 'static_library',
     'icu_directory': '../third_party/externals/icu'
   },
   'targets': [
     {
       'target_name': 'icuuc',
       'type': '<(component)',
       'sources': [
-        '<!@(python find.py ../third_party/externals/icu/source/common "*.c*")'
+        '<!@(python find.py "*.c*" ../third_party/externals/icu/source/common)'
       ],
       'defines': [
         'U_COMMON_IMPLEMENTATION',
         'U_HIDE_DATA_SYMBOL',
         'U_USING_ICU_NAMESPACE=0',
         'HAVE_DLOPEN=0',
         'UCONFIG_NO_NON_HTML5_CONVERSION=1',
       ],
       'include_dirs': [ '<(icu_directory)/source/common', ],
       'direct_dependent_settings': {
@@ skipping 93 matching lines @@
             'xcode_settings': {
               'GCC_ENABLE_CPP_RTTI': 'YES',  # -frtti
               'WARNING_CFLAGS': [ '-w' ],
             },
           }
         ],
       ], # conditions
     },
   ], # targets
 }