* archive.cc (Library_base::should_include_member): Pull in object
from archive if it defines the entry symbol.
* parameters.cc (Parameters::entry): New function.
* parameters.h (class Parameters): Declare entry.
* output.h (class Output_file_header): Remove entry_ field.
* output.cc (Output_file_header::Output_file_header): Remove entry
parameter. Change all callers.
(Output_file_header::entry): Use parameters->entry.
* gold.cc (queue_middle_tasks): Likewise.
* plugin.cc (Plugin_hook::run): Likewise.