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.

llvm-svn: 252385
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 906c872db9344ce483282938f83ee5d4a262f3e6
diff --git a/include/thread b/include/thread
index 3dde390..6857e9e 100644
--- a/include/thread
+++ b/include/thread
@@ -318,6 +318,7 @@
 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
     _LIBCPP_INLINE_VISIBILITY
     thread(thread&& __t) _NOEXCEPT : __t_(__t.__t_) {__t.__t_ = 0;}
+    _LIBCPP_INLINE_VISIBILITY
     thread& operator=(thread&& __t) _NOEXCEPT;
 #endif  // _LIBCPP_HAS_NO_RVALUE_REFERENCES
 
@@ -399,7 +400,7 @@
 
 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
 
-inline _LIBCPP_INLINE_VISIBILITY
+inline
 thread&
 thread::operator=(thread&& __t) _NOEXCEPT
 {