Factor linker flag which sets text segment into a function in SConstruct

src/untrusted/irt/nacl.scons

 # -*- python -*-
 # Copyright (c) 2012 The Native Client 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('env')
 
 # TODO(mseaborn): Enable -Wstrict-prototypes here.  Currently
 # dlmalloc/malloc.c does not build with this warning.
 env.FilterOut(CFLAGS=['-Wstrict-prototypes'])
 
 # This module shouldn't be built in an environment that uses glibc.
 if env.Bit('nacl_glibc'):
   raise UserError('src/untrusted/irt/nacl.scons in the wrong environment?')
 
 blob_env = env.Clone()
 blob_env.Append(LINKFLAGS=[blob_env.RodataSwitch('${IRT_BLOB_DATA_START}'),
-                           '-Wl,-Ttext-segment=${IRT_BLOB_CODE_START}'])
+                           blob_env.TextSwitch('${IRT_BLOB_CODE_START}')])
 
 irt_support_sources = [
     'irt_malloc.c',
     'irt_private_pthread.c',
     'irt_private_tls.c',
     ]
 
 irt_entry_obj = blob_env.ComponentObject('irt_entry.c')
 
 # NACL_GC_WRAP_SYSCALL uses ({...}) syntax.
@@ skipping 96 matching lines @@
     and not env.Bit('built_elsewhere')):
   check_tls_arch = '${TARGET_FULLARCH}'
   if env.Bit('build_arm'):
     check_tls_arch = 'arm'
   node = env.CommandTest('irt_core_tls_test.out',
                          ['${PYTHON}', env.File('check_tls.py'),
                           check_tls_arch, '${OBJDUMP}', irt_core_library],
                          # don't run ${PYTHON} under the emulator.
                          direct_emulation=False)
   env.AddNodeToTestSuite(node, ['small_tests'], 'run_irt_core_tls_test')