Fixed Xcode warnings

src/render/SDL_render.c

@@ -892,7 +892,7 @@ static SDL_INLINE void VerifyDrawQueueFunctions(const SDL_Renderer *renderer)
     SDL_assert(renderer->RunCommandQueue != NULL);
 }
 
-static SDL_RenderLineMethod SDL_GetRenderLineMethod()
+static SDL_RenderLineMethod SDL_GetRenderLineMethod(void)
 {
     const char *hint = SDL_GetHint(SDL_HINT_RENDER_LINE_METHOD);
 

src/render/opengles2/SDL_shaders_gles2.c

@@ -380,7 +380,7 @@ const char *GLES2_GetShaderInclude(GLES2_ShaderIncludeType type)
     }
 }
 
-GLES2_ShaderIncludeType GLES2_GetTexCoordPrecisionEnumFromHint()
+GLES2_ShaderIncludeType GLES2_GetTexCoordPrecisionEnumFromHint(void)
 {
     const char *texcoord_hint = SDL_GetHint("SDL_RENDER_OPENGLES2_TEXCOORD_PRECISION");
     GLES2_ShaderIncludeType value = GLES2_SHADER_FRAGMENT_INCLUDE_BEST_TEXCOORD_PRECISION;