add unix_sockets_posix module to build system and fix compilation errors
diff --git a/vsprojects/vcxproj/grpc/grpc.vcxproj b/vsprojects/vcxproj/grpc/grpc.vcxproj
index c2635c3..ac87537 100644
--- a/vsprojects/vcxproj/grpc/grpc.vcxproj
+++ b/vsprojects/vcxproj/grpc/grpc.vcxproj
@@ -348,6 +348,7 @@
     <ClInclude Include="$(SolutionDir)\..\src\core\iomgr\timer.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\iomgr\timer_heap.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\iomgr\udp_server.h" />
+    <ClInclude Include="$(SolutionDir)\..\src\core\iomgr\unix_sockets_posix.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\iomgr\wakeup_fd_pipe.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\iomgr\wakeup_fd_posix.h" />
     <ClInclude Include="$(SolutionDir)\..\src\core\iomgr\workqueue.h" />
@@ -560,6 +561,10 @@
     </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\iomgr\udp_server.c">
     </ClCompile>
+    <ClCompile Include="$(SolutionDir)\..\src\core\iomgr\unix_sockets_posix.c">
+    </ClCompile>
+    <ClCompile Include="$(SolutionDir)\..\src\core\iomgr\unix_sockets_posix_noop.c">
+    </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\iomgr\wakeup_fd_eventfd.c">
     </ClCompile>
     <ClCompile Include="$(SolutionDir)\..\src\core\iomgr\wakeup_fd_nospecial.c">