fix compilation error on macOS.
fix compilation error on macOS.

AmiArt/treefrog-framework,treefrogframework/treefrog-framework,treefrogframework/treefrog-framework,AmiArt/treefrog-framework,AmiArt/treefrog-framework,treefrogframework/treefrog-framework,treefrogframework/treefrog-framework,AmiArt/treefrog-framework,AmiArt/treefrog-framework,treefrogframework/treefrog-framework