diff --git a/CMakeLists.txt b/CMakeLists.txt
index 6f07d3ada..a257cceab 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -13,6 +13,20 @@ else(${CMAKE_MAJOR_VERSION} GREATER 2 OR ${CMAKE_MINOR_VERSION} GREATER 7)
 	set( NO_GENERATOR_EXPRESSIONS ON )
 endif(${CMAKE_MAJOR_VERSION} GREATER 2 OR ${CMAKE_MINOR_VERSION} GREATER 7)
 
+# Function to get a recursive list of files, but also get the directory names
+# as well unlike GLOB_RECURSE
+function( glob_recurse_with_directories OUTVAR DIR )
+	file( GLOB CHILDREN ${DIR}/* )
+	foreach( CHILD ${CHILDREN} )
+		if( IS_DIRECTORY ${CHILD} )
+			set( TEMP_LIST "" )
+			glob_recurse_with_directories( TEMP_LIST ${CHILD} )
+			set( ${OUTVAR} ${${OUTVAR}} ${TEMP_LIST} )
+		endif( IS_DIRECTORY ${CHILD} )
+	endforeach( CHILD ${CHILDREN} )
+	set( ${OUTVAR} ${${OUTVAR}} ${CHILDREN} PARENT_SCOPE )
+endfunction( glob_recurse_with_directories )
+
 # Simplify pk3 building, add_pk3(filename srcdirectory)
 function( add_pk3 PK3_NAME PK3_DIR )
 	get_target_property(ZIPDIR_EXE zipdir LOCATION)
@@ -23,15 +37,18 @@ function( add_pk3 PK3_NAME PK3_DIR )
 		set( PK3_TARGET "pk3" )
 	endif( ${PK3_TARGET} STREQUAL "zdoom_pk3" )
 
+	# Get as many files as we can to depend on.
+	glob_recurse_with_directories( PK3_DEPENDS ${PK3_DIR} )
+
 	if( NOT NO_GENERATOR_EXPRESSIONS AND NOT ZDOOM_OUTPUT_OLDSTYLE )
 		add_custom_command( OUTPUT ${ZDOOM_OUTPUT_DIR}/${PK3_NAME}
 			COMMAND ${ZIPDIR_EXE} -udf ${ZDOOM_OUTPUT_DIR}/${PK3_NAME} ${PK3_DIR}
 			COMMAND ${CMAKE_COMMAND} -E copy_if_different ${ZDOOM_OUTPUT_DIR}/${PK3_NAME} $<TARGET_FILE_DIR:zdoom>/${PK3_NAME}
-			DEPENDS zipdir ${PK3_DIR} )
+			DEPENDS zipdir ${PK3_DIR} ${PK3_DEPENDS} )
 	else( NOT NO_GENERATOR_EXPRESSIONS AND NOT ZDOOM_OUTPUT_OLDSTYLE )
 		add_custom_command( OUTPUT ${ZDOOM_OUTPUT_DIR}/${PK3_NAME}
 			COMMAND ${ZIPDIR_EXE} -udf ${ZDOOM_OUTPUT_DIR}/${PK3_NAME} ${PK3_DIR}
-			DEPENDS zipdir ${PK3_DIR} )
+			DEPENDS zipdir ${PK3_DIR} ${PK3_DEPENDS} )
 	endif( NOT NO_GENERATOR_EXPRESSIONS AND NOT ZDOOM_OUTPUT_OLDSTYLE )
 
 	add_custom_target( ${PK3_TARGET} ALL