# Without this patch, the first local include of unwind.h might, with the 
# __has_include_next, try to include the one from the system.
# It might be /usr/include/clang/3.4/include/unwind.h
# Because of the #ifndef __CLANG_UNWIND_H, it might never include any declaration
# from the system. 

Index: llvm-toolchain-snapshot_3.5~svn201843/clang/lib/Headers/unwind.h
===================================================================
--- llvm-toolchain-snapshot_3.5~svn201843.orig/clang/lib/Headers/unwind.h	2014-02-21 11:12:42.154418157 +0100
+++ llvm-toolchain-snapshot_3.5~svn201843/clang/lib/Headers/unwind.h	2014-02-21 11:12:42.150418157 +0100
@@ -23,9 +23,6 @@
 
 /* See "Data Definitions for libgcc_s" in the Linux Standard Base.*/
 
-#ifndef __CLANG_UNWIND_H
-#define __CLANG_UNWIND_H
-
 #if __has_include_next(<unwind.h>)
 /* Darwin (from 11.x on) and libunwind provide an unwind.h. If that's available,
  * use it. libunwind wraps some of its definitions in #ifdef _GNU_SOURCE,
@@ -53,6 +50,9 @@
 # endif
 #else
 
+#ifndef __CLANG_UNWIND_H
+#define __CLANG_UNWIND_H
+
 #include <stdint.h>
 
 #ifdef __cplusplus
@@ -275,6 +275,7 @@
 }
 #endif
 
+#endif /* __CLANG_UNWIND_H */
+
 #endif
 
-#endif /* __CLANG_UNWIND_H */