* scripttempl/pe.sc: Specify the output arch, which Ian says is
the Right Thing to do.
* emultempl/pe.em: various changes to parameterize the
target-specific information.
(gld_i386pe_after_open): Detect and fix MS import libraries
by renaming the member objects (which are all named the same).
* pe-dll.c: various changes to parameterize the target-specific
information.
(generate_reloc): support relocs more generically to allow for
expansion.
(pe_exe_build_sections): new; used to add .relocs to .exes
(pe_exe_fill_sections): ditto
output_section_callback, gc_section_callback): New functions for
generic section walks.
(wild, lang_gc_wild): Use walk_wild.
(wild_file, lang_gc_wild_file): Deleted. Common logic moved to
walk_wild_file.
(wild_section, lang_gc_wild_section): Deleted. Common logic moved
to walk_fild_section. Unique logic moved into callbacks
output_section_callback and gc_section_callback.
