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
15 files changed