MSVC: compat: make the POSIX shims available to all targets

Some of them have been already defined, but others are being added via
submodules. Best just make them available everywhere.
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9a6bad1..c3ce0c9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -364,6 +364,7 @@
         target_include_directories(yangobj PRIVATE ${COMPAT_POSIX_INCLUDES})
     endif()
     target_include_directories(yang PRIVATE ${COMPAT_POSIX_INCLUDES})
+    include_directories(${COMPAT_POSIX_INCLUDES})
 
     find_package(pthreads REQUIRED)
     target_link_libraries(yang PThreads4W::PThreads4W)