Build and use libraries locally in the nacl build, not requiring "partial SDK"

src/untrusted/pthread/nacl.scons

 # -*- python -*-
 # Copyright (c) 2011 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')
 
 # (elijahtaylor): Removing so braced groups will work for GC syscall wrapping.
 env.FilterOut(CCFLAGS=['-pedantic'])
 
 valgrind = env.ComponentObject(
     'valgrind_annotations.o',
     '${MAIN_DIR}/src/untrusted/valgrind/dynamic_annotations.c')
 
 env.ComponentLibrary('libpthread', ['nc_thread.c',
                                     'nc_mutex.c',
                                     'nc_condvar.c',
                                     'nc_semaphore.c',
                                     'nc_spinlock.c',
                                     'nc_hash.c',
                                     valgrind
                                     ])
 
 env.AddLibraryToSdk(['libpthread'])
 
-dest_dir = ARGUMENTS.get('extra_sdk_include_destination',
-                         '${NACL_SDK_INCLUDE}')
-Alias('install_libpthread',
-       # Copy the header file to the include directory.
-       [env.Replicate(dest_dir, ['pthread.h', 'semaphore.h' ])])
+# install_libpthread is a no-op under --nacl_glibc, but without it
+# installs the header files from this directory into the toolchain.
+if not env.Bit('nacl_glibc'):
+  n = env.AddHeaderToSdk(['pthread.h', 'semaphore.h'], None)
+else:
+  n = []
+env.Alias('install_libpthread', n)