install the desktop files on OpenBSD too

Index: CMakeLists.txt
--- CMakeLists.txt.orig
+++ CMakeLists.txt
@@ -272,7 +272,7 @@ install (DIRECTORY resources
 )
 
 # Install desktop shortcuts for Linux
-if (${CMAKE_SYSTEM_NAME} MATCHES "Linux")
+if ((${CMAKE_SYSTEM_NAME} MATCHES "Linux") OR (${CMAKE_SYSTEM_NAME} MATCHES "OpenBSD"))
 	message ("Installing desktop files")
 
 	# Install icons