class RbSys::Mkmf::Config

Config that delegates to CargoBuilder if needded

def cross_compiling? 

def cross_compiling?
  RbConfig::CONFIG["CROSS_COMPILING"] == "yes"
end

def initialize(builder) 

def initialize(builder)
  @builder = builder
  @force_install_rust_toolchain = false
  @auto_install_rust_toolchain = true
  @clean_after_install = rubygems_invoked?
  @rubygems_clean_dirs = ["./cargo-vendor"]
end

def method_missing(name, *args, &blk) 

def method_missing(name, *args, &blk)
  @builder.send(name, *args, &blk)
end

def respond_to_missing?(name, include_private = false) 

def respond_to_missing?(name, include_private = false)
  @builder.respond_to?(name) || super
end

def rubygems_invoked?

install, to remove bloat.
We want to know this so we can cleanup the target directory after an
Seems to be the only way to reliably know if we were invoked by Rubygems. 
def rubygems_invoked?
  ENV.key?("SOURCE_DATE_EPOCH")
end