diff --git a/src/Makefile.sources b/src/Makefile.sources
index 911ee2f54..cbbad90d2 100644
--- a/src/Makefile.sources
+++ b/src/Makefile.sources
@@ -163,7 +163,6 @@ HB_BASE_sources = \
 	hb-unicode.hh \
 	hb-utf.hh \
 	hb-vector.hh \
-	hb-warning.cc \
 	hb.hh \
 	$(NULL)
 
diff --git a/src/harfbuzz.cc b/src/harfbuzz.cc
index fe1c36023..251a0654d 100644
--- a/src/harfbuzz.cc
+++ b/src/harfbuzz.cc
@@ -44,7 +44,6 @@
 #include "hb-static.cc"
 #include "hb-ucd.cc"
 #include "hb-unicode.cc"
-#include "hb-warning.cc"
 #include "hb-glib.cc"
 #include "hb-ft.cc"
 #include "hb-graphite2.cc"
diff --git a/src/hb-atomic.hh b/src/hb-atomic.hh
index 09d88937c..b3fb296b4 100644
--- a/src/hb-atomic.hh
+++ b/src/hb-atomic.hh
@@ -212,18 +212,7 @@ static inline bool _hb_compare_and_swaplp (long *P, long O, long N)
 static_assert ((sizeof (long) == sizeof (void *)), "");
 
 
-#elif !defined(HB_NO_MT)
-
-#define HB_ATOMIC_INT_NIL 1 /* Warn that fallback implementation is in use. */
-
-#define _hb_memory_barrier()			do {} while (0)
-
-#define hb_atomic_int_impl_add(AI, V)		((*(AI) += (V)) - (V))
-
-#define hb_atomic_ptr_impl_cmpexch(P,O,N)	(* (void **) (P) == (void *) (O) ? (* (void **) (P) = (void *) (N), true) : false)
-
-
-#else /* HB_NO_MT */
+#elif defined(HB_NO_MT)
 
 #define hb_atomic_int_impl_add(AI, V)		((*(AI) += (V)) - (V))
 
@@ -232,6 +221,11 @@ static_assert ((sizeof (long) == sizeof (void *)), "");
 #define hb_atomic_ptr_impl_cmpexch(P,O,N)	(* (void **) (P) == (void *) (O) ? (* (void **) (P) = (void *) (N), true) : false)
 
 
+#else
+
+#error "Could not find any system to define atomic_int macros."
+#error "Check hb-atomic.hh for possible resolutions."
+
 #endif
 
 
diff --git a/src/hb-mutex.hh b/src/hb-mutex.hh
index e13626731..e7f8b1c43 100644
--- a/src/hb-mutex.hh
+++ b/src/hb-mutex.hh
@@ -92,25 +92,7 @@ typedef volatile int hb_mutex_impl_t;
 #define hb_mutex_impl_finish(M)	HB_STMT_START {} HB_STMT_END
 
 
-#elif !defined(HB_NO_MT)
-
-#if defined(HAVE_SCHED_H) && defined(HAVE_SCHED_YIELD)
-# include <sched.h>
-# define HB_SCHED_YIELD() sched_yield ()
-#else
-# define HB_SCHED_YIELD() HB_STMT_START {} HB_STMT_END
-#endif
-
-#define HB_MUTEX_INT_NIL 1 /* Warn that fallback implementation is in use. */
-typedef volatile int hb_mutex_impl_t;
-#define HB_MUTEX_IMPL_INIT	0
-#define hb_mutex_impl_init(M)	*(M) = 0
-#define hb_mutex_impl_lock(M)	HB_STMT_START { while (*(M)) HB_SCHED_YIELD (); (*(M))++; } HB_STMT_END
-#define hb_mutex_impl_unlock(M)	(*(M))--
-#define hb_mutex_impl_finish(M)	HB_STMT_START {} HB_STMT_END
-
-
-#else /* HB_NO_MT */
+#elif defined(HB_NO_MT)
 
 typedef int hb_mutex_impl_t;
 #define HB_MUTEX_IMPL_INIT	0
@@ -120,6 +102,11 @@ typedef int hb_mutex_impl_t;
 #define hb_mutex_impl_finish(M)	HB_STMT_START {} HB_STMT_END
 
 
+#else
+
+#error "Could not find any system to define mutex macros."
+#error "Check hb-mutex.hh for possible resolutions."
+
 #endif
 
 
diff --git a/src/hb-warning.cc b/src/hb-warning.cc
deleted file mode 100644
index 60c7445b7..000000000
--- a/src/hb-warning.cc
+++ /dev/null
@@ -1,37 +0,0 @@
-/*
- * Copyright © 2012  Google, Inc.
- *
- *  This is part of HarfBuzz, a text shaping library.
- *
- * Permission is hereby granted, without written agreement and without
- * license or royalty fees, to use, copy, modify, and distribute this
- * software and its documentation for any purpose, provided that the
- * above copyright notice and the following two paragraphs appear in
- * all copies of this software.
- *
- * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
- * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
- * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
- * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
- * DAMAGE.
- *
- * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
- * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
- * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
- * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
- * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
- *
- * Google Author(s): Behdad Esfahbod
- */
-
-#include "hb.hh"
-
-#ifdef HB_ATOMIC_INT_NIL
-#error "Could not find any system to define atomic_int macros, library WILL NOT be thread-safe"
-#error "Check hb-atomic.hh for possible resolutions."
-#endif
-
-#ifdef HB_MUTEX_IMPL_NIL
-#error "Could not find any system to define mutex macros, library WILL NOT be thread-safe"
-#error "Check hb-mutex.hh for possible resolutions."
-#endif