diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..5322a25
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "externals/tz/tz"]
+	path = externals/tz/tz
+	url = https://github.com/eggert/tz.git
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8c47574..87c8950 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,11 +2,7 @@ cmake_minimum_required(VERSION 3.10)
 
 project(tzdb2nx VERSION 1.0)
 
-set(TZDB_VERSION "$ENV{TZDB_VERSION}")
-if ("${TZDB_VERSION}" STREQUAL "")
-    set(TZDB_VERSION "2022c")
-endif()
-
 set(CMAKE_CXX_STANDARD 20)
 
+add_subdirectory(externals)
 add_subdirectory(src)
diff --git a/externals/CMakeLists.txt b/externals/CMakeLists.txt
new file mode 100644
index 0000000..33a9c7c
--- /dev/null
+++ b/externals/CMakeLists.txt
@@ -0,0 +1 @@
+add_subdirectory(tz)
diff --git a/externals/tz/CMakeLists.txt b/externals/tz/CMakeLists.txt
new file mode 100644
index 0000000..eacd3be
--- /dev/null
+++ b/externals/tz/CMakeLists.txt
@@ -0,0 +1,34 @@
+set(TZ_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/tz")
+set(TZ_DIR "${CMAKE_CURRENT_BINARY_DIR}/tz")
+set(TZ_ZONEINFO_DIR "${TZ_DIR}/usr/share/zoneinfo" CACHE PATH "Time zone info data directory")
+set(TZIF_LIST_FILE "${CMAKE_CURRENT_BINARY_DIR}/tzif_list.txt" CACHE PATH "List of zone info files")
+
+find_program(GNU_MAKE make)
+if ("${GNU_MAKE}" STREQUAL "GNU_MAKE-NOTFOUND")
+    message(FATAL_ERROR "GNU make not found")
+endif()
+
+if (NOT EXISTS "${TZ_DIR}" OR NOT EXISTS "${TZIF_LIST_FILE}")
+    execute_process(
+        COMMAND
+            ${GNU_MAKE} DESTDIR=${TZ_DIR} install
+        WORKING_DIRECTORY 
+            ${TZ_SOURCE_DIR}
+        COMMAND_ERROR_IS_FATAL ANY
+    )
+
+    # Step taken by Arch Linux packaging, but Nintendo apparently skips it
+    # execute_process(
+    #     COMMAND
+    #         "${TZDB_LOCATION}/zic" -b fat -d ${TZDB_ZONEINFO} africa antarctica asia australasia europe northamerica southamerica etcetera backward factory
+    #     WORKING_DIRECTORY
+    #         "${TZDB_LOCATION}"
+    #     COMMAND_ERROR_IS_FATAL ANY
+    # )
+
+    execute_process(
+        COMMAND
+            /bin/bash "${CMAKE_CURRENT_SOURCE_DIR}/find_tzif.sh" "${TZ_ZONEINFO_DIR}" "${TZIF_LIST_FILE}"
+        COMMAND_ERROR_IS_FATAL ANY
+    )
+endif()
diff --git a/src/tzdb/find_tzif.sh b/externals/tz/find_tzif.sh
similarity index 100%
rename from src/tzdb/find_tzif.sh
rename to externals/tz/find_tzif.sh
diff --git a/externals/tz/tz b/externals/tz/tz
new file mode 160000
index 0000000..ce4d776
--- /dev/null
+++ b/externals/tz/tz
@@ -0,0 +1 @@
+Subproject commit ce4d77644d2793027bb27f095dec7b530edcd947
diff --git a/src/tzdb/CMakeLists.txt b/src/tzdb/CMakeLists.txt
index 3bd7688..b91ed63 100644
--- a/src/tzdb/CMakeLists.txt
+++ b/src/tzdb/CMakeLists.txt
@@ -1,21 +1,10 @@
-find_program(GNU_MAKE make)
-if ("${GNU_MAKE}" STREQUAL "GNU_MAKE-NOTFOUND")
-    message(ERROR "make program not found")
-endif()
+set(NX_TZDB_DIR "${CMAKE_CURRENT_BINARY_DIR}/nx" CACHE PATH "Path to Switch-style time zone data")
+set(NX_ZONEINFO_DIR "${NX_TZDB_DIR}/zoneinfo")
 
-set(TZDB_ARCHIVE "tzdb-${TZDB_VERSION}.tar.lz")
-set(TZDB_LOCATION "${CMAKE_CURRENT_BINARY_DIR}/tzdb-${TZDB_VERSION}")
-if (NOT (EXISTS "${CMAKE_CURRENT_BINARY_DIR}/${TZDB_ARCHIVE}" AND EXISTS "${TZDB_LOCATION}"))
-    file(DOWNLOAD "https://data.iana.org/time-zones/releases/${TZDB_ARCHIVE}" "${CMAKE_CURRENT_BINARY_DIR}/${TZDB_ARCHIVE}")
-    file(ARCHIVE_EXTRACT INPUT "${CMAKE_CURRENT_BINARY_DIR}/${TZDB_ARCHIVE}" DESTINATION "${CMAKE_CURRENT_BINARY_DIR}")
-endif()
-
-set(TZDB_BUILD_DIR "${CMAKE_CURRENT_BINARY_DIR}/build")
-set(TZDB_ZONEINFO "${TZDB_BUILD_DIR}/usr/share/zoneinfo")
-set(TZIF_LIST_FILE "${CMAKE_CURRENT_BINARY_DIR}/tzif_list.txt")
-
-set(NX_BUILD_DIR "${PROJECT_BINARY_DIR}/nx")
-set(NX_ZONEINFO_DIR "${NX_BUILD_DIR}/zoneinfo")
+set(TZDB_VERSION_FILE ${TZDB_LOCATION}/version)
+file(TIMESTAMP ${TZDB_VERSION_FILE} TZDB_VERSION "%y%m%d" UTC)
+set(NX_VERSION_FILE ${NX_TZDB_DIR}/version.txt)
+file(WRITE ${NX_VERSION_FILE} "${TZDB_VERSION}")
 
 add_custom_target(x80e 
     ALL
@@ -23,37 +12,7 @@ add_custom_target(x80e
         tzdb2nx
         ${NX_VERSION_FILE})
 
-if (NOT EXISTS "${TZDB_BUILD_DIR}" OR NOT EXISTS ${TZIF_LIST_FILE})
-    execute_process(
-        COMMAND
-            "${GNU_MAKE}" DESTDIR=${TZDB_BUILD_DIR} install
-        WORKING_DIRECTORY 
-            "${TZDB_LOCATION}"
-        COMMAND_ERROR_IS_FATAL ANY
-    )
-
-    # Step taken by Arch Linux packaging, but Nintendo apparently skips it
-    # execute_process(
-    #     COMMAND
-    #         "${TZDB_LOCATION}/zic" -b fat -d ${TZDB_ZONEINFO} africa antarctica asia australasia europe northamerica southamerica etcetera backward factory
-    #     WORKING_DIRECTORY
-    #         "${TZDB_LOCATION}"
-    #     COMMAND_ERROR_IS_FATAL ANY
-    # )
-
-    execute_process(
-        COMMAND
-            /bin/bash "${CMAKE_CURRENT_SOURCE_DIR}/find_tzif.sh" "${TZDB_ZONEINFO}" "${TZIF_LIST_FILE}"
-        COMMAND_ERROR_IS_FATAL ANY
-    )
-endif()
-
-set(TZDB_VERSION_FILE ${TZDB_LOCATION}/version)
-file(TIMESTAMP ${TZDB_VERSION_FILE} TZDB_VERSION "%y%m%d" UTC)
-set(NX_VERSION_FILE ${NX_BUILD_DIR}/version.txt)
-file(WRITE ${NX_VERSION_FILE} "${TZDB_VERSION}")
-
-set(BINARY_LIST_TXT ${NX_BUILD_DIR}/binaryList.txt)
+set(BINARY_LIST_TXT ${NX_TZDB_DIR}/binaryList.txt)
 add_custom_target(binary_list
         bash ${CMAKE_CURRENT_SOURCE_DIR}/generate_binary_list_txt.sh ${BINARY_LIST_TXT}
     BYPRODUCTS
@@ -64,7 +23,7 @@ add_dependencies(x80e binary_list)
 
 file(STRINGS "${TZIF_LIST_FILE}" TZ_FILES)
 foreach(FILE ${TZ_FILES})
-    file(RELATIVE_PATH TARG "${TZDB_ZONEINFO}" "${FILE}")
+    file(RELATIVE_PATH TARG "${TZ_ZONEINFO_DIR}" "${FILE}")
     get_filename_component(TARG_PATH "${NX_ZONEINFO_DIR}/${TARG}" DIRECTORY)
     string(REGEX REPLACE "\/" "_" TARG_SANITIZED "${TARG}")
     add_custom_target(${TARG_SANITIZED}
@@ -73,10 +32,9 @@ foreach(FILE ${TZ_FILES})
         COMMAND
             mkdir -p ${TARG_PATH}
         COMMAND
-            "${PROJECT_BINARY_DIR}/src/tzdb2nx/tzdb2nx" ${FILE} ${NX_ZONEINFO_DIR}/${TARG}
+            ${TZDB2NX_PATH} ${FILE} ${NX_ZONEINFO_DIR}/${TARG}
         DEPENDS
-            tzdb2nx
-    )
+            tzdb2nx)
 
     add_dependencies(x80e ${TARG_SANITIZED})
     add_dependencies(binary_list ${TARG_SANITIZED})
diff --git a/src/tzdb2nx/CMakeLists.txt b/src/tzdb2nx/CMakeLists.txt
index 9d2b034..ae5d614 100644
--- a/src/tzdb2nx/CMakeLists.txt
+++ b/src/tzdb2nx/CMakeLists.txt
@@ -2,3 +2,6 @@ add_executable(tzdb2nx
     main.cpp
     tzif.cpp
     tzif.h)
+
+set(TZDB2NX_PATH "${CMAKE_CURRENT_BINARY_DIR}/tzdb2nx" CACHE PATH "Path to tzdb2nx path")
+set_target_properties(tzdb2nx PROPERTIES CMAKE_RUNTIME_OUTPUT_DIRECTORY ${TZDB2NX_PATH})