diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9d7da1644d..50af339166 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -49,11 +49,13 @@ function( add_pk3 PK3_NAME PK3_DIR )
 			DEPENDS zipdir )
 	endif()
 
-	# Touch the zipdir executable here so that the pk3s are forced to
-	# rebuild each time since their dependecy has "changed."
-	add_custom_target( ${PK3_TARGET} ALL
-		COMMAND ${CMAKE_COMMAND} -E touch $<TARGET_FILE:zipdir>
-		DEPENDS ${ZDOOM_OUTPUT_DIR}/${PK3_NAME} )
+		file(GLOB PK3_SRCS ${PK3_DIR}/*)
+		# Touch the zipdir executable here so that the pk3s are forced to
+		# rebuild each time since their dependecy has "changed."
+		add_custom_target( ${PK3_TARGET} ALL
+			COMMAND ${CMAKE_COMMAND} -E touch $<TARGET_FILE:zipdir>
+			DEPENDS ${ZDOOM_OUTPUT_DIR}/${PK3_NAME}
+			SOURCES "${PK3_SRCS}")
 endfunction()
 
 # Macro for building libraries without debugging information