mac: remove libc++-static 10.6 compatibility hack

third_party/libc++-static/libcxxabi.patch

Index: third_party/libc++-static/libcxxabi.patch
diff --git a/third_party/libc++-static/libcxxabi.patch b/third_party/libc++-static/libcxxabi.patch
deleted file mode 100644
index dfdf7662ac8dc4c455fb3491a74d9a407016bca7..0000000000000000000000000000000000000000
--- a/third_party/libc++-static/libcxxabi.patch
+++ /dev/null
@@ -1,17 +0,0 @@
---- src/cxa_default_handlers.cpp    (revision 245965)
-+++ src/cxa_default_handlers.cpp    (working copy)
-@@ -46,13 +46,7 @@
-                         exception_header + 1;
-                 const __shim_type_info* thrown_type =
-                     static_cast<const __shim_type_info*>(exception_header->exceptionType);
--                // Try to get demangled name of thrown_type
--                int status;
--                char buf[1024];
--                size_t len = sizeof(buf);
--                const char* name = __cxa_demangle(thrown_type->name(), buf, &len, &status);
--                if (status != 0)
--                    name = thrown_type->name();
-+                const char* name = thrown_type->name();
-                 // If the uncaught exception can be caught with std::exception&
-                 const __shim_type_info* catch_type =
- 				 static_cast<const __shim_type_info*>(&typeid(std::exception));