gnu: Add dicedb.

* gnu/packages/databases.scm (dicedb): New variable.
* gnu/packages/patches/dicedb-remove-init-from-config-subpkg.patch:
New file.
* gnu/local.mk (dist_patch_DATA): Register patch.

Change-Id: Id5c97d254c35301181593b42c96a83a1ef843131
Signed-off-by: Ludovic Courtès <ludo@gnu.org>

gnu/packages/patches/dicedb-remove-init-from-config-subpkg.patch

@@ -0,0 +1,50 @@
+If built locally, dicedb works for as long as the build cache in the tmp
+directory exists - it looks for a file called VERSION in the project root.
+Once cleared, or in the case of downloading from substitute server, the
+location of the VERSION file is invalid. Removing this code and instead
+providing them through the flag resolves this issue.
+
+diff --git a/config/config.go b/config/config.go
+index b358813..c408096 100644
+--- a/config/config.go
++++ b/config/config.go
+@@ -9,8 +9,6 @@ import (
+ 	"os"
+ 	"path/filepath"
+ 	"reflect"
+-	"runtime"
+-	"strings"
+ 
+ 	"github.com/spf13/pflag"
+ 	"github.com/spf13/viper"
+@@ -20,30 +18,6 @@ var (
+ 	DiceDBVersion = "-"
+ )
+ 
+-// init initializes the DiceDBVersion variable by reading the
+-// VERSION file from the project root.
+-// This function runs automatically when the package is imported.
+-func init() {
+-	// Get the absolute path of the current file (config.go)
+-	// using runtime reflection
+-	_, currentFile, _, _ := runtime.Caller(0) //nolint:dogsled
+-
+-	// Navigate up two directories from config.go to reach the project root
+-	// (config.go is in the config/ directory, so we need to go up twice)
+-	projectRoot := filepath.Dir(filepath.Dir(currentFile))
+-
+-	// Read the VERSION file from the project root
+-	// This approach works regardless of where the program is executed from
+-	version, err := os.ReadFile(filepath.Join(projectRoot, "VERSION"))
+-	if err != nil {
+-		slog.Error("could not read the version file", slog.String("error", err.Error()))
+-		os.Exit(1)
+-	}
+-
+-	// Store the version string in the package-level DiceDBVersion variable
+-	DiceDBVersion = strings.TrimSpace(string(version))
+-}
+-
+ var Config *DiceDBConfig
+ 
+ type DiceDBConfig struct {