diff --git a/m4/blocks.m4 b/m4/blocks.m4
index 49ee2a3..0c7a28f 100644
--- a/m4/blocks.m4
+++ b/m4/blocks.m4
@@ -50,15 +50,34 @@ AS_IF([test "x$dispatch_cv_cblocks" != "xno"], [
       ], [
 	AC_MSG_RESULT([-lBlocksRuntime])
       ], [
+        LIBS="$saveLIBS -lobjc"
+	AC_TRY_LINK([], [
+	  ^{ int k; k=0; }();
+ 	], [
+	  need_libobjc=yes;
+	  AC_MSG_RESULT([-lobjc])
+	], [
 	AC_MSG_ERROR([can't find Blocks runtime])
       ])
     ])
+    ])
+
+    AS_IF([test "x$need_libobjc" = "xyes"], [
+	AC_CHECK_HEADER([objc/blocks_private.h], [
+	    AC_DEFINE(BLOCKS_RUNTIME_FROM_LIBOBJC, 1, Define if the Blocks runtime resides in libobjc)
+	], [
+	    AC_MSG_ERROR([libobjc does not provide objc/blocks_private.h])
+	])
+    ], [
+	:
+    ])   
     CFLAGS="$saveCFLAGS"
     have_cblocks=true
 ], [
     CBLOCKS_FLAGS=""
     have_cblocks=false
 ])
+
 AM_CONDITIONAL(HAVE_CBLOCKS, $have_cblocks)
 AC_SUBST([CBLOCKS_FLAGS])
 
diff --git a/src/internal.h b/src/internal.h
index a69b36a..5ffaac5 100644
--- a/src/internal.h
+++ b/src/internal.h
@@ -130,8 +130,13 @@
 #if TARGET_OS_WIN32
 #define BLOCK_EXPORT extern "C" __declspec(dllexport)
 #endif /* TARGET_OS_WIN32 */
+#ifndef BLOCKS_RUNTIME_FROM_LIBOBJC
 #include <Block_private.h>
 #include <Block.h>
+#else
+#include <objc/blocks_private.h>
+#include <objc/blocks_runtime.h>
+#endif /* BLOCKS_RUNTIME_FROM_LIBOBJC */
 #endif /* __BLOCKS__ */
 
 #include <assert.h>
diff --git a/testing/dispatch_after.c b/testing/dispatch_after.c
index dc4a3e7..eb01f72 100644
--- a/testing/dispatch_after.c
+++ b/testing/dispatch_after.c
@@ -27,7 +27,11 @@
 #include <assert.h>
 
 #include "dispatch_test.h"
+#ifndef BLOCKS_RUNTIME_FROM_LIBOBJC
 #include <Block.h>
+#else
+#include <objc/blocks_runtime.h>
+#endif /* BLOCKS_RUNTIME_FROM_LIBOBJC */
 
 void done(void *arg __attribute__((unused))) {
     sleep(1);