glslangValidator with global include paths?

[SpiderPig]

I wanted to try and compile some shaders in a location away from the validator and the .glsl files.  It compiles fine so long as I don't try to include anything in the shader.

The BAT file;

C:\UltraEngine\Tools\glslangValidator.exe "C:\_output\Test.frag" -V -o "C:\_output\Test.frag.spv"

The Shader;

#version 450
#extension GL_GOOGLE_include_directive : enable
#extension GL_ARB_separate_shader_objects : enable
#extension GL_EXT_multiview : enable

//Compiles if this line is commented out
#include "C:\UltraEngine\Templates\Common\Shaders\Base\Materials.glsl"

layout(location = 0) out vec4 outColor;

void main()
{
	outColor = vec4(0.0f, 1.0f, 1.0f, 1.0f);
}

Does the validator only use relative paths somhow?

[SpiderPig]

And the answer is : 

#include "../../../../../../../../UltraEngine/Templates/Common/Shaders\Base\Materials.glsl"

Relatively speaking.