Revert "[libc++] Build <filesystem> support as part of the dylib"

When I applied r356500 (https://reviews.llvm.org/D59152), I somehow
deleted all of filesystem's tests. I will revert r356500 and re-apply
it properly.

llvm-svn: 356505

2 files changed, 32 insertions, 0 deletions

diff --git a/libcxx/docs/BuildingLibcxx.rst b/libcxx/docs/BuildingLibcxx.rst
index cb00b89edc1..01f442de3ba 100644
--- a/libcxx/docs/BuildingLibcxx.rst
+++ b/libcxx/docs/BuildingLibcxx.rst
@@ -224,6 +224,18 @@ libc++experimental Specific Options
   Install libc++experimental.a alongside libc++.
 
 
+.. option:: LIBCXX_ENABLE_FILESYSTEM:BOOL
+
+  **Default**: ``ON``
+
+  Build filesystem as a standalone library libc++fs.a.
+
+.. option:: LIBCXX_INSTALL_FILESYSTEM_LIBRARY:BOOL
+
+  **Default**: ``LIBCXX_ENABLE_FILESYSTEM AND LIBCXX_INSTALL_LIBRARY``
+
+  Install libc++fs.a alongside libc++.
+
 .. _ABI Library Specific Options:
 
 ABI Library Specific Options
diff --git a/libcxx/docs/UsingLibcxx.rst b/libcxx/docs/UsingLibcxx.rst
index 2055a5ab65d..7b06189c648 100644
--- a/libcxx/docs/UsingLibcxx.rst
+++ b/libcxx/docs/UsingLibcxx.rst
@@ -50,6 +50,23 @@ An example of using ``LD_LIBRARY_PATH``:
   $ ./a.out # Searches for libc++ along LD_LIBRARY_PATH
 
 
+Using ``<filesystem>`` and libc++fs
+====================================
+
+Libc++ provides the implementation of the filesystem library in a separate
+library. Users of ``<filesystem>`` and ``<experimental/filesystem>`` are
+required to link ``-lc++fs``.
+
+.. note::
+  Prior to libc++ 7.0, users of ``<experimental/filesystem>`` were required
+  to link libc++experimental.
+
+.. warning::
+  The Filesystem library is still experimental in nature. As such normal
+  guarantees about ABI stability and backwards compatibility do not yet apply
+  to it. In the future, this restriction will be removed.
+
+
 Using libc++experimental and ``<experimental/...>``
 =====================================================
 
@@ -66,6 +83,9 @@ installed. For information on building libc++experimental from source see
 :ref:`Building Libc++ <build instructions>` and
 :ref:`libc++experimental CMake Options <libc++experimental options>`.
 
+Note that as of libc++ 7.0 using the ``<experimental/filesystem>`` requires linking
+libc++fs instead of libc++experimental.
+
 Also see the `Experimental Library Implementation Status <http://libcxx.llvm.org/ts1z_status.html>`__
 page.