GLSL: Separate sources and standalone validation

Question

I want to be able to do these things:

• Write GLSL shaders
• Separate my sources for reusability purposes
• Validate all my sources before building the main application, and exit if anything fails

The GLSL standard is written so that you can specify multiple source strings to a single shader, and it will combine them. Shaders will also pass verification with C-style prototype-and implementation structure. For example, the following pseudocode shader:

#version 460
out vec4 color;

vec4 getColor() {
    return vec4(0.0, 1.0, 0.0, 0.0);
}

void main() {
    color = getColor();
}

Could be separated into this string:

#version 460
out vec4 color;

vec4 getColor();

void main() {
    color = getColor();
}

and this string:

vec4 getColor() {
    return vec4(0.0, 1.0, 0.0, 0.0);
}

By putting each in its own file to pass to glslangvalidator, I would hope you could validate them separately.

But there's a problem, and that problem is the #version directive. If I specify #version 460 at the start of all my sources, then when OpenGL combines them, the #version will be defined twice, which is not allowed. But if I don't, glslangvalidator will assume version 100, and the sources will not validate properly.

I've considered a few options:

• Dynamically remove the #version directive using string manipulation function when I read the source files to embed the sources in the application. This sounds like it could work, but it also feels like a hacky workaround.
• Dynamically add the #version directive to a duplicate file and run glslangvalidator against that instead. This also sounds like it could work, but it raises doubt about the validity of the validation (it validated against a slightly different source, after all).
• Specify the GLSL version at command line. For some reason, the tool only seems to accept version 100 at command line, when I need version 460.
• #ifndef gates. The validator raises an error with this because #version has to be the very first thing in the source, without even an exception allowed for preprocessor ifs.

Is there a canonical solution to this? Perhaps something I've overlooked in the GLSL spec, or an additional flag for the validator, or even an alternate tool I can use?