diff --git a/CMakeLists.txt b/CMakeLists.txt
index 951d874..2373eb5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,8 +8,19 @@ set( GRIVE_VERSION "0.5.1-dev" )
 # common compile options
 add_definitions( -DVERSION="${GRIVE_VERSION}" )
 add_definitions( -D_FILE_OFFSET_BITS=64 -std=c++0x )
+if ( APPLE )
+	add_definitions( -Doff64_t=off_t )
+endif ( APPLE )
+
+find_program(
+	HAVE_SYSTEMD systemd
+	PATHS /lib/systemd /usr/lib/systemd
+	NO_DEFAULT_PATH
+)
+if ( HAVE_SYSTEMD )
+	add_subdirectory( systemd )
+endif( NOT HAVE_SYSTEMD )
 
-add_subdirectory( systemd )
 add_subdirectory( libgrive )
 add_subdirectory( grive )
-	
\ No newline at end of file
+