ABI: Fix for undefined "___cxa_deleted_virtual" symbol in MacOSX

Patch from Eddie Elizondo. Reviewed as D37830 (https://reviews.llvm.org/D37830).

On MacOSX the following program:

struct S { virtual void f() = delete; };
int main() { new S; }
Fails with the following error:

Undefined symbols for architecture x86_64:
  "___cxa_deleted_virtual"
This adds a fix to export the needed symbols.

Test:

> lit -sv test/libcxx/language.support/cxa_deleted_virtual.pass.cpp
> Testing Time: 0.21s
>   Expected Passes    : 1

llvm-svn: 313500
diff --git a/libcxx/lib/libc++sjlj-abi.exp b/libcxx/lib/libc++sjlj-abi.exp
index e646df1..f494e17 100644
--- a/libcxx/lib/libc++sjlj-abi.exp
+++ b/libcxx/lib/libc++sjlj-abi.exp
@@ -12,6 +12,7 @@
 ___cxa_guard_release
 ___cxa_rethrow
 ___cxa_pure_virtual
+___cxa_deleted_virtual
 ___cxa_begin_catch
 ___cxa_throw
 ___cxa_vec_cctor