diff --git a/webrtc/build/common.gypi b/webrtc/build/common.gypi
index 8be9ecc412..64c2a6eb00 100644
--- a/webrtc/build/common.gypi
+++ b/webrtc/build/common.gypi
@@ -204,6 +204,16 @@
       }, {
         'conditions': [
           ['os_posix==1', {
+	    'configurations': {
+              'Debug_Base': {
+                'defines': [
+                  # Chromium's build/common.gypi defines this for all posix
+                  # _except_ for ios & mac.  We want it there as well, e.g.
+                  # because ASSERT and friends trigger off of it.
+                  '_DEBUG',
+                ],
+              },
+            },
             'conditions': [
               # -Wextra is currently disabled in Chromium's common.gypi. Enable
               # for targets that can handle it. For Android/arm64 right now
diff --git a/webrtc/libjingle/xmllite/xmlelement_unittest.cc b/webrtc/libjingle/xmllite/xmlelement_unittest.cc
index 0f20e751e7..257899aba1 100644
--- a/webrtc/libjingle/xmllite/xmlelement_unittest.cc
+++ b/webrtc/libjingle/xmllite/xmlelement_unittest.cc
@@ -240,7 +240,7 @@ class XmlElementCreatorThread : public rtc::Thread {
 
 // If XmlElement creation and destruction isn't thread safe,
 // this test should crash.
-TEST(XmlElementTest, DISABLED_ON_MAC(TestMultithread)) {
+TEST(XmlElementTest, TestMultithread) {
   int thread_count = 2;  // Was 100, but that's too slow.
   int elem_count = 100;  // Was 100000, but that's too slow.
   buzz::QName qname("foo", "bar");