build/linux-x86_64-debug/mesa/libmesa.a(glspirv.os): In function `_mesa_SpecializeShaderARB':
mesa/src/mesa/main/glspirv.c:170: undefined reference to `gl_spirv_validation'

Bisected to:
ba975140d3c99b60c63846c3c08bd158f7c95d42 is the first bad commit
commit ba975140d3c99b60c63846c3c08bd158f7c95d42
Author: Nicolai Hähnle <nicolai.haehnle@amd.com>
Date:   Sat Jun 10 21:36:24 2017 +0200
    mesa: Implement glSpecializeShaderARB
    
    v2:
      * Use gl_spirv_validation instead of spirv_to_nir.  This method just
        validates the shader. The conversion to NIR will happen later,
        during linking. (Alejandro Piñeiro)
      * Use gl_shader_spirv_data struct to store the SPIR-V data.
        (Eduardo Lima)
      * Use the 'spirv_data' member to tell if the gl_shader is a SPIR-V
        shader, instead of a dedicated flag. (Timothy Arceri)
    
    Signed-off-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
    Signed-off-by: Alejandro Piñeiro <apinheiro@igalia.com>
    Signed-off-by: Eduardo Lima Mitev <elima@igalia.com>
    
    Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>