Switch nacl-clang back to gas in SCons

tests/thread_suspension/nacl.scons

Index: tests/thread_suspension/nacl.scons
diff --git a/tests/thread_suspension/nacl.scons b/tests/thread_suspension/nacl.scons
index 30db1955770da69246ece7306f4f777f927ec858..0fa9cf1f70cd0ddcdacb2e84375b28f5cfeddc14 100644
--- a/tests/thread_suspension/nacl.scons
+++ b/tests/thread_suspension/nacl.scons
@@ -31,14 +31,8 @@ node = env.CommandTest('thread_suspension_test.out',
 
 # This test is flaky on mac10.7-newlib-dbg-asan.
 # See https://code.google.com/p/nativeclient/issues/detail?id=3906
-# nacl-clang's integrated assembler expands "naclcall" to a sequence which
-# separates the push of the return address from the jump, and so breaks the
-# test's expectations for the stack pointer.
-# TODO(dschuff): re-enable this test after we switch to gas with nacl-clang
-# https://code.google.com/p/nativeclient/issues/detail?id=3966
 is_broken= (not env.Bit('nacl_static_link') or
-            (env.Bit('asan') and env.Bit('host_mac')) or
-            env.Bit('nacl_clang'))
+            (env.Bit('asan') and env.Bit('host_mac')))
 
 env.AddNodeToTestSuite(node, ['small_tests', 'nonpexe_tests'],
                        'run_thread_suspension_test', is_broken=is_broken)