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/crawl-ref/source/database.cc	2018-08-09 21:49:26.000000000 -0400
+++ b/crawl-ref/source/database.cc	2018-10-07 18:06:41.022445789 -0400
@@ -24,6 +24,7 @@
 #include "stringutil.h"
 #include "syscalls.h"
 #include "unicode.h"
+#include "version.h"
 
 // TextDB handles dependency checking the db vs text files, creating the
 // db, loading, and destroying the DB.
@@ -54,6 +55,7 @@
     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;
@@ -246,7 +254,7 @@
         ts += buf;
     }
 
-    if (no_files)
+    if (no_files && version.empty())
     {
         // No point in empty databases, although for simplicity keep ones
         // for disappeared translations for now.
@@ -312,7 +320,10 @@
             _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;
log/gnu/packages/patches?id=a92c6b1a2b5b8b69f248c732db4a11ddf130f0f1'>patches</a>/<a href='/guix/log/gnu/packages/patches/icedtea-7-hotspot-gcc-segfault-workaround.patch?id=a92c6b1a2b5b8b69f248c732db4a11ddf130f0f1'>icedtea-7-hotspot-gcc-segfault-workaround.patch</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/packages/patches/icedtea-7-hotspot-gcc-segfault-workaround.patch?id=a92c6b1a2b5b8b69f248c732db4a11ddf130f0f1&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2018-07-03 00:53:56 +0200'>2018-07-03</span></td><td><a href='/guix/commit/gnu/packages/patches/icedtea-7-hotspot-gcc-segfault-workaround.patch?id=db024183c9fa93289a45e816529e99001de0a7d1'>gnu: icedtea: Work around gcc segfault.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/java.scm (icedtea-7)[native-inputs]: Add patch to hotspot.
* gnu/packages/patches/icedtea-7-hotspot-gcc-segfault-workaround.patch:
New file.
* gnu/local.mk (dist_patch_DATA): Add it.
</span></span></td><td>Gábor Boskovits</td></tr>
guix-package-net.sh,
tests/guix-package.sh: Use the shell '!' keyword to negate command exit status
in place of 'if ...; then false; else true; fi'
</span></span></td><td>Eric Bavier</td></tr>
<tr><td><span title='2020-08-23 23:05:16 +0200'>2020-08-23</span></td><td><a href='/guix/commit/tests/guix-lint.sh?id=d10474c38d58bdc676e64336769dc2e00cdfa8ed'>lint: formatting: Gracefully handle relative file names.</a><span class='msg-avail'>...<span class='msg-tooltip'>Fixes &lt;https://bugs.gnu.org/42543&gt;.
Reported by Jack Hill &lt;jackhill@jackhill.us&gt;.

* guix/lint.scm (check-formatting): Always return a list (previously we
would return #f when 'search-path' returns #f).  Check whether
LOCATION's file is a relative file name.  Return a warning if not.
* tests/guix-lint.sh: Add test.
</span></span></td><td>Ludovic Courtès</td></tr>