shaderc compile through api with #include
It is your responsibility to support includes by instantiating an IncluderInterface instance and calling SetIncluder(...) on the options instance.  

The interface includer API consists of the following methods:

// Handles shaderc_include_resolver_fn callbacks.
virtual shaderc_include_result* GetInclude(const char* requested_source,
                                           shaderc_include_type type,
                                           const char* requesting_source,
                                           size_t include_depth) = 0;

// Handles shaderc_include_result_release_fn callbacks.
virtual void ReleaseInclude(shaderc_include_result* data) = 0;


It will therefore also be your responsibility to implement these functions and interpret the #include directives from the GLSL into shaderc_include_result instances that will be used by shaderc to complete the preprocessing of the GLSL.