Store the crawl version in the textdatabases in SAVEDIR and
upgrade the databases when the crawl version changes.

By default crawl checks for a mtime difference on files in DATADIR to see if an
upgrade is required, but guix nulls all file dates,
and crawl would never upgrade saves.

diff -ur a/source/database.cc b/source/database.cc
--- a/source/database.cc	2018-08-09 21:49:26.000000000 -0400
+++ b/source/database.cc	2018-10-07 18:06:41.022445789 -0400
@@ -25,6 +25,7 @@
 #include "syscalls.h"
 #include "threads.h"
 #include "unicode.h"
+#include "version.h"
 
 // TextDB handles dependency checking the db vs text files, creating the
 // db, loading, and destroying the DB.
@@ -55,6 +56,7 @@
     vector<string> _input_files;
     DBM* _db;
     string timestamp;
+    string version;
     TextDB *_parent;
     const char* lang() { return _parent ? Options.lang_name : 0; }
 public:
@@ -163,7 +165,7 @@
 
 TextDB::TextDB(const char* db_name, const char* dir, vector<string> files)
     : _db_name(db_name), _directory(dir), _input_files(files),
-      _db(nullptr), timestamp(""), _parent(0), translation(0)
+      _db(nullptr), timestamp(""), version(""),  _parent(0), translation(0)
 {
 }
 
@@ -171,7 +173,7 @@
     : _db_name(parent->_db_name),
       _directory(parent->_directory + Options.lang_name + "/"),
       _input_files(parent->_input_files), // FIXME: pointless copy
-      _db(nullptr), timestamp(""), _parent(parent), translation(nullptr)
+      _db(nullptr), timestamp(""), version(""), _parent(parent), translation(nullptr)
 {
 }
 
@@ -186,6 +188,9 @@
         return false;
 
     timestamp = _query_database(*this, "TIMESTAMP", false, false, true);
+    version = _query_database(*this, "VERSION", false, false, true);
+    if (version.empty())
+        return false;
     if (timestamp.empty())
         return false;
 
@@ -229,6 +234,9 @@
     string ts;
     bool no_files = true;
 
+    if (string(Version::Long) != version)
+        return true;
+
     for (const string &file : _input_files)
     {
         string full_input_path = _directory + file;
@@ -245,7 +253,7 @@
         ts += buf;
     }
 
-    if (no_files && timestamp.empty())
+    if (no_files && timestamp.empty() && version.empty())
     {
         // No point in empty databases, although for simplicity keep ones
         // for disappeared translations for now.
@@ -313,7 +321,10 @@
             _store_text_db(full_input_path, _db);
         }
     }
+
+    string current_version = string(Version::Long);
     _add_entry(_db, "TIMESTAMP", ts);
+    _add_entry(_db, "VERSION", current_version);
 
     dbm_close(_db);
     _db = 0;
msg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-04-02 12:35:30 +0200'>2023-04-02</span></td><td><a href='/guix/commit/gnu/services/security.scm?id=0fbb356714f4ae3ea18e4997131a0e1746cc923c'>services: replace bare serializers with (serializer ...)</a><span class='msg-avail'>...</span></td><td>Bruno Victal</td></tr>
<tr><td><span title='2023-01-10 10:47:27 -0500'>2023-01-10</span></td><td><a href='/guix/commit/gnu/services/security.scm?id=dc403ec7f15cdb94a43654a941b25894cff707c7'>gnu: services: Fix fail2ban configuration serialization.</a><span class='msg-avail'>...</span></td><td>muradm</td></tr>
<tr><td><span title='2022-12-06 17:49:50 +0100'>2022-12-06</span></td><td><a href='/guix/commit/gnu/services/security.scm?id=a420b4f34e7449319f6ec73301ffb932845b66d6'>services: fail2ban: Start server in the foreground.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-12-06 17:07:46 +0100'>2022-12-06</span></td><td><a href='/guix/commit/gnu/services/security.scm?id=a508b5c7785bcd040c5a9e890be71ccd97f198fb'>services: fail2ban: Remove unnecessary Shepherd 'modules' field.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-12-06 17:07:12 +0100'>2022-12-06</span></td><td><a href='/guix/commit/gnu/services/security.scm?id=e45c83c3979c2554119fafdee7bb204d27e138b5'>services: fail2ban: 'stop' returns #f when the dameon is stopped.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-09-14 11:29:11 -0400'>2022-09-14</span></td><td><a href='/guix/commit/gnu/services/security.scm?id=29d52a56f2d254781b65dbec0f1009db0b9d06e6'>gnu: fail2ban-service-type: Improve extra-content fields.</a><span class='msg-avail'>...</span></td><td>muradm</td></tr>
<tr><td><span title='2022-09-01 08:58:16 -0400'>2022-09-01</span></td><td><a href='/guix/commit/gnu/services/security.scm?id=fa2d651475cc607a26ac87422747f5182c2f699a'>gnu: fail2ban-service-type: Fix documentation typos.</a><span class='msg-avail'>...</span></td><td>muradm</td></tr>
<tr><td><span title='2022-09-01 08:58:16 -0400'>2022-09-01</span></td><td><a href='/guix/commit/gnu/services/security.scm?id=7686dd9676ebd54aec96ab22f0942e27a0979656'>gnu: fail2ban-service-type: Improve jail configuration serialization.</a><span class='msg-avail'>...</span></td><td>muradm</td></tr>
<tr><td><span title='2022-09-01 08:58:15 -0400'>2022-09-01</span></td><td><a href='/guix/commit/gnu/services/security.scm?id=80d9edb69d6e980501963fbae9c05e0c024295fe'>gnu: fail2ban-service-type: Fix field name serialization.</a><span class='msg-avail'>...</span></td><td>muradm</td></tr>
<tr><td><span title='2022-08-28 21:46:30 -0400'>2022-08-28</span></td><td><a href='/guix/commit/gnu/services/security.scm?id=3c2d2b453832167df02f4aa25de4857a003fbecf'>gnu: security: Add fail2ban-service-type.</a><span class='msg-avail'>...</span></td><td>muradm</td></tr>