Generate debian package files with cmake

Used for the ppa builds, so it's nice if they still work.

CMakeLists.txt

@@ -2178,4 +2178,9 @@ if("${CMAKE_SYSTEM_NAME}" STREQUAL "Windows")
 	")
 
 	include(CPack)
+elseif("${CMAKE_SYSTEM_NAME}" STREQUAL "Linux")
+	file(COPY platform/unix/debian/ DESTINATION debian PATTERN "*.in" EXCLUDE)
+	configure_file(platform/unix/debian/control.in debian/control @ONLY)
+	configure_file(platform/unix/debian/changelog.in debian/changelog @ONLY)
+	configure_file(platform/unix/debian/rules.in debian/rules @ONLY)
 endif()