Cleanup: move visibility/linkage attributes to the first declaration.

This change moves visibility attributes from out-of-class method
definitions to in-class declaration. This is needed for a switch to
attribute((internal_linkage)) (see http://reviews.llvm.org/D13925)
which can only appear on the first declaration.

This change does not touch istream/ostream/streambuf. They are
handled separately in http://reviews.llvm.org/D14409.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@252385 91177308-0d34-0410-b5e6-96231b3b80d8

include/__mutex_base

@@ -308,6 +308,7 @@ public:
 
     template <class _Rep, class _Period, class _Predicate>
         bool
+        _LIBCPP_INLINE_VISIBILITY
         wait_for(unique_lock<mutex>& __lk,
                  const chrono::duration<_Rep, _Period>& __d,
                  _Predicate __pred);
@@ -392,7 +393,7 @@ condition_variable::wait_for(unique_lock<mutex>& __lk,
 }
 
 template <class _Rep, class _Period, class _Predicate>
-inline _LIBCPP_INLINE_VISIBILITY
+inline
 bool
 condition_variable::wait_for(unique_lock<mutex>& __lk,
                              const chrono::duration<_Rep, _Period>& __d,