build the logging example in CMake builds

Summary:
Add a CMakeLists.txt file to build the logging example program in CMake
builds.

This also disables the `AsyncFileWriter.fork` test on Windows, since `fork()`
isn't available on Windows.

Reviewed By: yfeldblum

Differential Revision: D21332968

fbshipit-source-id: b578df92576e79d34b7fe2bf79dc8f30e0fd6d6b

folly/CMakeLists.txt

@@ -27,6 +27,7 @@ install(
 )
 
 add_subdirectory(experimental/exception_tracer)
+add_subdirectory(logging/example)
 
 if (PYTHON_EXTENSIONS)
   # Create tree of symbolic links in structure required for successful

folly/logging/example/CMakeLists.txt

+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+add_executable(logging_example main.cpp)
+target_link_libraries(logging_example logging_example_lib folly)
+
+add_library(logging_example_lib lib.cpp)
+target_link_libraries(logging_example_lib folly)

folly/logging/test/AsyncFileWriterTest.cpp

@@ -618,6 +618,7 @@ TEST(AsyncFileWriter, discard) {
   readStats.check();
 }
 
+#ifndef _WIN32
 /**
  * Test that AsyncFileWriter operates correctly after a fork() in both the
  * parent and child processes.
@@ -803,3 +804,4 @@ TEST(AsyncFileWriter, crazyForks) {
   SKIP() << "pthread_atfork() is not supported on this platform";
 #endif // FOLLY_HAVE_PTHREAD_ATFORK
 }
+#endif // !_WIN32