Designate some headers as internal
diff --git a/src/Makefile.am b/src/Makefile.am
index 5379c0a..f1516ba 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -14,9 +14,9 @@
 nobase_include_HEADERS += sdeventplus/exception.hpp
 libsdeventplus_la_SOURCES += sdeventplus/exception.cpp
 
-nobase_include_HEADERS += sdeventplus/sdevent.hpp
-libsdeventplus_la_SOURCES += sdeventplus/sdevent.cpp
+nobase_include_HEADERS += sdeventplus/internal/sdevent.hpp
+libsdeventplus_la_SOURCES += sdeventplus/internal/sdevent.cpp
 
-nobase_include_HEADERS += sdeventplus/sdref.hpp
+nobase_include_HEADERS += sdeventplus/internal/sdref.hpp
 
 nobase_include_HEADERS += sdeventplus/test/sdevent.hpp
diff --git a/src/sdeventplus/event.cpp b/src/sdeventplus/event.cpp
index 1baca16..a955f41 100644
--- a/src/sdeventplus/event.cpp
+++ b/src/sdeventplus/event.cpp
@@ -1,6 +1,7 @@
 #include <functional>
 #include <sdeventplus/event.hpp>
 #include <sdeventplus/exception.hpp>
+#include <systemd/sd-event.h>
 
 namespace sdeventplus
 {
diff --git a/src/sdeventplus/event.hpp b/src/sdeventplus/event.hpp
index e2372bb..3cde1d5 100644
--- a/src/sdeventplus/event.hpp
+++ b/src/sdeventplus/event.hpp
@@ -1,8 +1,8 @@
 #pragma once
 
 #include <memory>
-#include <sdeventplus/sdevent.hpp>
-#include <sdeventplus/sdref.hpp>
+#include <sdeventplus/internal/sdevent.hpp>
+#include <sdeventplus/internal/sdref.hpp>
 #include <systemd/sd-event.h>
 
 namespace sdeventplus
diff --git a/src/sdeventplus/internal/sdevent.cpp b/src/sdeventplus/internal/sdevent.cpp
new file mode 100644
index 0000000..cf992ef
--- /dev/null
+++ b/src/sdeventplus/internal/sdevent.cpp
@@ -0,0 +1,6 @@
+#include <sdeventplus/internal/sdevent.hpp>
+
+namespace sdeventplus
+{
+SdEventImpl sdevent_impl;
+}
diff --git a/src/sdeventplus/sdevent.hpp b/src/sdeventplus/internal/sdevent.hpp
similarity index 100%
rename from src/sdeventplus/sdevent.hpp
rename to src/sdeventplus/internal/sdevent.hpp
diff --git a/src/sdeventplus/sdref.hpp b/src/sdeventplus/internal/sdref.hpp
similarity index 97%
rename from src/sdeventplus/sdref.hpp
rename to src/sdeventplus/internal/sdref.hpp
index 492ae70..b6e2ba2 100644
--- a/src/sdeventplus/sdref.hpp
+++ b/src/sdeventplus/internal/sdref.hpp
@@ -2,7 +2,7 @@
 
 #include <functional>
 #include <memory>
-#include <sdeventplus/sdevent.hpp>
+#include <sdeventplus/internal/sdevent.hpp>
 #include <type_traits>
 
 namespace sdeventplus
diff --git a/src/sdeventplus/sdevent.cpp b/src/sdeventplus/sdevent.cpp
deleted file mode 100644
index d145f38..0000000
--- a/src/sdeventplus/sdevent.cpp
+++ /dev/null
@@ -1,6 +0,0 @@
-#include <sdeventplus/sdevent.hpp>
-
-namespace sdeventplus
-{
-SdEventImpl sdevent_impl;
-}
diff --git a/src/sdeventplus/test/sdevent.hpp b/src/sdeventplus/test/sdevent.hpp
index b467647..7cea28d 100644
--- a/src/sdeventplus/test/sdevent.hpp
+++ b/src/sdeventplus/test/sdevent.hpp
@@ -1,7 +1,7 @@
 #pragma once
 
 #include <gmock/gmock.h>
-#include <sdeventplus/sdevent.hpp>
+#include <sdeventplus/internal/sdevent.hpp>
 #include <systemd/sd-event.h>
 
 namespace sdeventplus
diff --git a/test/sdref.cpp b/test/sdref.cpp
index 6bb5410..ab004f5 100644
--- a/test/sdref.cpp
+++ b/test/sdref.cpp
@@ -1,7 +1,6 @@
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
-#include <sdeventplus/sdevent.hpp>
-#include <sdeventplus/sdref.hpp>
+#include <sdeventplus/internal/sdref.hpp>
 #include <sdeventplus/test/sdevent.hpp>
 #include <systemd/sd-event.h>
 #include <type_traits>