cmake: Add user specifiable version variable

Previously it was still using the submodule's version.

CMakeLists.txt

@@ -3,6 +3,11 @@ cmake_minimum_required(VERSION 3.10)
 project(tzdb2nx VERSION 1.0)
 
 option(TZDB2NX_ZONEINFO_DIR "Specify a custom zoneinfo directory containing time zone data you wish to use" "")
+option(TZDB2NX_VERSION "Specify a custom zoneinfo version with the directory" "")
+
+if ((TZDB2NX_ZONEINFO_DIR AND NOT TZDB2NX_VERSION) OR (TZDB2NX_VERSION AND NOT TZDB2NX_ZONEINFO_DIR))
+    message(FATAL_ERROR "Either TZDB2NX_ZONEINFO_DIR or TZDB2NX_VERSION but not both were defined.")
+endif()
 
 set(CMAKE_CXX_STANDARD 20)
 

src/tzdb/CMakeLists.txt

@@ -13,7 +13,10 @@ set(NX_ZONEINFO_DIR "${NX_TZDB_DIR}/zoneinfo")
 
 set(TZDB_VERSION_FILE ${TZ_SOURCE_DIR}/NEWS)
 
-execute_process(
+if (NOT "${TZDB2NX_VERSION}" STREQUAL "")
+    set(TZDB_VERSION "${TZDB2NX_VERSION}\n")
+else()
+    execute_process(
         COMMAND 
             ${GIT_PROGRAM} log --pretty=%at -n1 NEWS
         OUTPUT_VARIABLE
@@ -22,20 +25,21 @@ execute_process(
             ${TZ_SOURCE_DIR}
         COMMAND_ERROR_IS_FATAL ANY)
 
-string(REPLACE "\n" "" TZ_COMMIT_TIME "${TZ_COMMIT_TIME}")
+    string(REPLACE "\n" "" TZ_COMMIT_TIME "${TZ_COMMIT_TIME}")
 
-if (APPLE OR CMAKE_SYSTEM_NAME MATCHES "DragonFly|FreeBSD|NetBSD|OpenBSD")
+    if (APPLE OR CMAKE_SYSTEM_NAME MATCHES "DragonFly|FreeBSD|NetBSD|OpenBSD")
         set(VERSION_COMMAND ${GNU_DATE} -r ${TZ_COMMIT_TIME} +%y%m%d)
-else ()
+    else ()
         set(VERSION_COMMAND ${GNU_DATE} +%y%m%d --date=@${TZ_COMMIT_TIME})
-endif ()
+    endif ()
 
-execute_process(
+    execute_process(
         COMMAND
             ${VERSION_COMMAND}
         OUTPUT_VARIABLE
             TZDB_VERSION
         COMMAND_ERROR_IS_FATAL ANY)
+endif()
 
 set(NX_VERSION_FILE ${NX_TZDB_DIR}/version.txt)
 file(WRITE ${NX_VERSION_FILE} "${TZDB_VERSION}")