bug: fix loading non-mlx models when ollama is built with mlx support (#14211)

This change fixes an issue where GGML based models (for either the Ollama runner or
the legacy llama.cpp runner) would try to load the mlx library. That would panic
and the model fails to start.

x/mlxrunner/mlx/dynamic.go

@@ -8,6 +8,7 @@ package mlx
 import "C"
 
 import (
+	"fmt"
 	"io/fs"
 	"log/slog"
 	"os"
@@ -16,6 +17,13 @@ import (
 	"unsafe"
 )
 
+var initError error
+
+// CheckInit returns any error that occurred during MLX dynamic library initialization.
+func CheckInit() error {
+	return initError
+}
+
 func init() {
 	switch runtime.GOOS {
 	case "darwin":
@@ -34,7 +42,9 @@ func init() {
 	for _, path := range filepath.SplitList(paths) {
 		matches, err := fs.Glob(os.DirFS(path), "libmlxc.*")
 		if err != nil {
-			panic(err)
+			initError = fmt.Errorf("failed to glob for MLX libraries in %s: %w", path, err)
+			slog.Warn("MLX dynamic library not available", "error", initError)
+			return
 		}
 
 		for _, match := range matches {
@@ -61,5 +71,6 @@ func init() {
 		}
 	}
 
-	panic("Failed to load any MLX dynamic library")
+	initError = fmt.Errorf("failed to load any MLX dynamic library from OLLAMA_LIBRARY_PATH=%s", paths)
+	slog.Warn("MLX dynamic library not available", "error", initError)
 }

x/mlxrunner/server.go

@@ -7,6 +7,7 @@ import (
 	"cmp"
 	"encoding/json"
 	"flag"
+	"fmt"
 	"io"
 	"log/slog"
 	"net/http"
@@ -16,12 +17,17 @@ import (
 
 	"github.com/ollama/ollama/envconfig"
 	"github.com/ollama/ollama/logutil"
+	"github.com/ollama/ollama/x/mlxrunner/mlx"
 	"github.com/ollama/ollama/x/mlxrunner/sample"
 )
 
 func Execute(args []string) error {
 	slog.SetDefault(logutil.NewLogger(os.Stderr, envconfig.LogLevel()))
 
+	if err := mlx.CheckInit(); err != nil {
+		return fmt.Errorf("MLX not available: %w", err)
+	}
+
 	var (
 		modelName string
 		port      int