Don't require -DSK_USE_POSIX_THREADS.

src/utils/SkCondVar.h

Index: src/utils/SkCondVar.h
diff --git a/src/utils/SkCondVar.h b/src/utils/SkCondVar.h
index 7f4225c66ac1d9550e428efc8ab43979ec3f3911..0a9f94f0abebf44dcc322ad1cbfe59bf09907770 100644
--- a/src/utils/SkCondVar.h
+++ b/src/utils/SkCondVar.h
@@ -10,12 +10,10 @@
 
 #include "SkTypes.h"
 
-#ifdef SK_USE_POSIX_THREADS
-    #include <pthread.h>
-#elif defined(SK_BUILD_FOR_WIN32)
+#ifdef SK_BUILD_FOR_WIN32
     #include <windows.h>
 #else
-    #error "SkCondVar requires pthreads or Windows."
+    #include <pthread.h>
 #endif
 
 /**
@@ -64,12 +62,12 @@ public:
     void broadcast();
 
 private:
-#ifdef SK_USE_POSIX_THREADS
-    pthread_mutex_t  fMutex;
-    pthread_cond_t   fCond;
-#elif defined(SK_BUILD_FOR_WIN32)
+#ifdef SK_BUILD_FOR_WIN32
     CRITICAL_SECTION   fCriticalSection;
     CONDITION_VARIABLE fCondition;
+#else
+    pthread_mutex_t  fMutex;
+    pthread_cond_t   fCond;
 #endif
 };