Target workaround at non-Apple objective-c++ compilers only, as the previous

workaround broke those platforms. Pragmas push_macro and pop_macro are only
available on gcc 4.4 or later, so use plain ol' #define/#undef instead.


[SVN r66289]

libs/asio

@@ -1 +1 @@
-Subproject commit 200db06b39f5f5b2320045a48fdc0d1673a42bbd
+Subproject commit ddc92ac35f83d49295ebffa9de165edca75a720d