[libunwind] r285845 - Add support for old versions of MacOS to libunwind. Fixes PR22203. Thanks to Jeremy for the bug report and the patch.

[Marshall Clow via cfe-commits]

Author: marshall
Date: Wed Nov  2 12:56:05 2016
New Revision: 285845

URL: http://llvm.org/viewvc/llvm-project?rev=285845&view=rev
Log:
Add support for old versions of MacOS to libunwind. Fixes PR22203. Thanks to Jeremy for the bug report and the patch.

Modified:
    libunwind/trunk/include/libunwind.h

Modified: libunwind/trunk/include/libunwind.h
URL: http://llvm.org/viewvc/llvm-project/libunwind/trunk/include/libunwind.h?rev=285845&r1=285844&r2=285845&view=diff
==============================================================================
--- libunwind/trunk/include/libunwind.h (original)
+++ libunwind/trunk/include/libunwind.h Wed Nov  2 12:56:05 2016
@@ -20,12 +20,26 @@
 #include <stddef.h>
 
 #ifdef __APPLE__
-  #include <Availability.h>
-    #ifdef __arm__
-       #define LIBUNWIND_AVAIL __attribute__((unavailable))
+  #if __clang__
+    #if __has_include(<Availability.h>)
+      #include <Availability.h>
+    #endif
+  #elif __ENVIRONMENT_MAC_OS_X_VERSION_MIN_REQUIRED__ >= 1050
+    #include <Availability.h>
+  #endif
+
+  #ifdef __arm__
+     #define LIBUNWIND_AVAIL __attribute__((unavailable))
+  #elif defined(__OSX_AVAILABLE_STARTING)
+    #define LIBUNWIND_AVAIL __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_5_0)
+  #else
+    #include <AvailabilityMacros.h>
+    #ifdef AVAILABLE_MAC_OS_X_VERSION_10_6_AND_LATER
+      #define LIBUNWIND_AVAIL AVAILABLE_MAC_OS_X_VERSION_10_6_AND_LATER
     #else
-      #define LIBUNWIND_AVAIL __OSX_AVAILABLE_STARTING(__MAC_10_6, __IPHONE_5_0)
+      #define LIBUNWIND_AVAIL __attribute__((unavailable))
     #endif
+  #endif
 #else
   #define LIBUNWIND_AVAIL
 #endif