GLSL Layout Qualifier Binding Points for out-dated OpenGL version

Question

The title is my question. Is there any replacement of 'binding' layout qualifier for OpenGL v 4.1?

I'm using MacOS and Xcode so if I run OpenGL 4.2 I got an error of glewinit saying 'Missing GL version'.

If I run this code with OpenGL 4.1, of course, it can't recognize 'binding' keyword.

My vertex shader code is :

#version 410

layout (location=0) in vec3 pos;
layout (location=1) in vec2 texCoord;

out vec2 tc;

uniform mat4 mv_matrix;
uniform mat4 proj_matrix;

layout (binding=0) uniform sampler2D samp;  // not used in vertex shader

void main(void) {
    gl_Position = proj_matrix * mv_matrix * vec4(pos, 1.0);
    tc = texCoord;
}

and my fragment shader code is :

#version 410

in vec2 tc;  // interpolated incoming texture coordinate

out vec4 color;

uniform mat4 mv_matrix;
uniform mat4 proj_matrix;

layout (binding=0) uniform sampler2D samp;

void main(void) {
    color = texture(samp, tc);
}

Answer 1

What do you mean by "replacement"? You can assign the uniform buffer binding point from OpenGL by using glUniformBlockBinding. But there's no other way to define it within the shader itself; after all, if there were, why would we need the binding qualifier in the first place?