libc++ fix

libcxx_fix.diff

diff --git a/lib/CMakeLists.txt b/lib/CMakeLists.txt
index d6a35f8..2be379a 100644
--- a/lib/CMakeLists.txt
+++ b/lib/CMakeLists.txt
@@ -90,6 +90,12 @@ if ( APPLE AND (LIBCXX_CXX_ABI_LIBNAME STREQUAL "libcxxabi" OR
     set(LIBCXX_LIBCPPABI_VERSION "2")
   endif()
 
+  if (DEFINED LIBCXX_CXX_ABI_LIBRARY_PATH)
+    set(OSX_ABI_LIBRARY_PATH "${LIBCXX_CXX_ABI_LIBRARY_PATH}/libc++abi.dylib")
+  else()
+    set(OSX_ABI_LIBRARY_PATH "${CMAKE_OSX_SYSROOT}/usr/lib/libc++abi.dylib")
+  endif()
+
   if ( CMAKE_OSX_DEPLOYMENT_TARGET STREQUAL "10.6" )
     add_definitions(-D__STRICT_ANSI__)
     add_link_flags(
@@ -104,14 +110,15 @@ if ( APPLE AND (LIBCXX_CXX_ABI_LIBNAME STREQUAL "libcxxabi" OR
       list(FIND ${CMAKE_OSX_ARCHITECTURES} "armv7" OSX_HAS_ARMV7)
       if (OSX_HAS_ARMV7)
         set(OSX_RE_EXPORT_LINE
-          "${CMAKE_OSX_SYSROOT}/usr/lib/libc++abi.dylib"
+          "${OSX_ABI_LIBRARY_PATH}"
           "-Wl,-reexported_symbols_list,${CMAKE_CURRENT_SOURCE_DIR}/libc++sjlj-abi.exp")
       else()
         set(OSX_RE_EXPORT_LINE
-          "-Wl,-reexport_library,${CMAKE_OSX_SYSROOT}/usr/lib/libc++abi.dylib")
+          "${OSX_ABI_LIBRARY_PATH} "
+          "-Wl,-reexport_library,${OSX_ABI_LIBRARY_PATH}")
       endif()
     else()
-      set(OSX_RE_EXPORT_LINE "/usr/lib/libc++abi.dylib -Wl,-reexported_symbols_list,${CMAKE_CURRENT_SOURCE_DIR}/libc++abi${LIBCXX_LIBCPPABI_VERSION}.exp")
+      set(OSX_RE_EXPORT_LINE "${OSX_ABI_LIBRARY_PATH}  -Wl,-reexported_symbols_list,${CMAKE_CURRENT_SOURCE_DIR}/libc++abi${LIBCXX_LIBCPPABI_VERSION}.exp")
     endif()
 
     add_link_flags(