Function do_build_shader_string

pub fn do_build_shader_string<F: FnMut(&str), G: Fn(&str) -> Cow<'static, str>>(
    gl_version: ShaderVersion,
    features: &[&str],
    kind: ShaderKind,
    base_filename: &str,
    get_source: &G,
    output: F,
)

Walks the given shader string and applies the output to the provided callback. Assuming an override path is not used, does no heap allocation and no I/O.