purego: refactor benchmark test to use internal load API

Replace direct purego.Dlopen/Dlclose calls with load.OpenLibrary/CloseLibrary
from the internal load package for consistency with other test code. Includes
proper error handling in the defer cleanup function.

Author: tmc

syscall_bench_test.go

@@ -10,6 +10,7 @@ import (
 	"testing"
 
 	"github.com/ebitengine/purego"
+	"github.com/ebitengine/purego/internal/load"
 )
 
 // BenchmarkCallingMethods compares RegisterFunc, SyscallN, and Callback methods
@@ -43,11 +44,15 @@ func BenchmarkCallingMethods(b *testing.B) {
 		os.Remove(libFileName)
 	})
 
-	libHandle, err := purego.Dlopen(libFileName, purego.RTLD_NOW|purego.RTLD_GLOBAL)
+	libHandle, err := load.OpenLibrary(libFileName)
 	if err != nil {
 		b.Fatalf("Failed to load C library: %v", err)
 	}
-	defer purego.Dlclose(libHandle)
+	defer func() {
+		if err := load.CloseLibrary(libHandle); err != nil {
+			b.Fatalf("Failed to close library: %s", err)
+		}
+	}()
 
 	// Create callbacks and load C functions
 	for i := range testCases {