template <class T, class U>
struct pair;
#ifndef _GLIBCXX_USE_FB
+FOLLY_GLIBCXX_NAMESPACE_CXX11_BEGIN
template <class T, class R, class A>
class basic_string;
+FOLLY_GLIBCXX_NAMESPACE_CXX11_END
#else
template <class T, class R, class A, class S>
class basic_string;
class vector;
template <class T, class A>
class deque;
+FOLLY_GLIBCXX_NAMESPACE_CXX11_BEGIN
template <class T, class A>
class list;
+FOLLY_GLIBCXX_NAMESPACE_CXX11_END
template <class T, class C, class A>
class set;
template <class K, class V, class C, class A>