#version directive in included files is problematic

Consider

// A.glsl
#version 410

// main.glsl
#version 410
#include <A.glsl>

void main() {}

will generate

// main.glsl
#version 410
#version 410

void main() {}

This is problematic, since the #version directive should only appear once. Furthermore, from https://www.khronos.org/opengl/wiki/Core_Language_(GLSL)#Version:

The #version directive must appear before anything else in a shader, save for whitespace and comments. If a #version directive does not appear at the top, then it assumes 1.10, which is almost certainly not what you want.

Use the A.glsl and main.glsl reproduction as the starting case, then locate the library entry point that expands #include directives. Add a regression test covering both files and verify that the generated shader contains only one #version directive while preserving the included content.