Index: buildbot/osuosl/master/config/builders.py
===================================================================
--- buildbot/osuosl/master/config/builders.py
+++ buildbot/osuosl/master/config/builders.py
@@ -667,8 +667,10 @@
          'slavenames': ['gribozavr4'],
          'builddir': 'libcxx-libcxxabi-singlethreaded-x86_64-linux-debian',
          'factory': LibcxxAndAbiBuilder.getLibcxxAndAbiBuilder(
-             env={'CC': 'clang', 'CXX': 'clang++',
-                  'CXXFLAGS' : '-D_LIBCPP_HAS_NO_THREADS -DLIBCXXABI_SINGLE_THREADED=1'}),
+             env={'CC': 'clang', 'CXX': 'clang++'},
+             additional_features=set(['libcxxabi-has-no-threads',
+                                      'libcpp-has-no-threads'
+                                      'libcpp-has-no-monotonic-clock'])),
          'category': 'libcxx'},
 
         {'name': 'libcxx-libcxxabi-x86_64-linux-ubuntu',
Index: zorg/buildbot/builders/LibcxxAndAbiBuilder.py
===================================================================
--- zorg/buildbot/builders/LibcxxAndAbiBuilder.py
+++ zorg/buildbot/builders/LibcxxAndAbiBuilder.py
@@ -42,7 +42,7 @@
     return f
 
 
-def getLibcxxAndAbiBuilder(f=None, env={}):
+def getLibcxxAndAbiBuilder(f=None, env={}, additional_features=set()):
     if f is None:
         f = buildbot.process.factory.BuildFactory()
 
@@ -59,6 +59,20 @@
 
     f = getLibcxxWholeTree(f, src_root)
 
+    if 'libcxxabi-has-no-threads' in additional_features:
+        env['CXXFLAGS'] += ' -DLIBCXXABI_HAS_NO_THREADS=1'
+
+    if 'libcpp-has-no-threads' in additional_features:
+        env['CXXFLAGS'] += ' -D_LIBCPP_HAS_NO_THREADS'
+
+    if 'libcpp-has-no-monotonic-clock' in additional_features:
+        env['CXXFLAGS'] += ' -D_LIBCPP_HAS_NO_MONOTONIC_CLOCK'
+
+    litTestArgs = ''
+    if additional_features:
+        litTestArgs = ('--param=additional_features=' +
+                       ','.join(additional_features))
+
     # Nuke/remake build directory and run CMake
     f.addStep(buildbot.steps.shell.ShellCommand(
         name='rm.builddir', command=['rm', '-rf', build_path],
@@ -83,13 +97,14 @@
               haltOnFailure=True, workdir=build_path))
 
     # Test libc++abi
+    lit_flags = properties.WithProperties("LIT_ARGS=%s" % litTestArgs)
     f.addStep(buildbot.steps.shell.ShellCommand(
-        name='test.libcxxabi', command=['make', 'check-libcxxabi'],
+        name='test.libcxxabi', command=['make', lit_flags, 'check-libcxxabi'],
         workdir=build_path))
 
     # Test libc++
     f.addStep(buildbot.steps.shell.ShellCommand(
-        name='test.libcxx', command=['make', 'check-libcxx'],
+        name='test.libcxx', command=['make', lit_flags, 'check-libcxx'],
         workdir=build_path))
 
     return f