Fix some gcc -Wall warnings:
* ldcref.c (output_cref): Add casts to avoid warnings.
* ldfile.c (ldfile_add_arch): Likewise.
* ldlang.c (lang_leave_overlay_section): Likewise.
* lexsup.c (OPTION_COUNT): Likewise.
(parse_args): Likewise.
* emultempl/elf32.em (gld${EMULATION_NAME}_place_orphan):
Likewise.
* emultempl/sunos.em (gld${EMULATION_NAME}_search_dir): Likewise.
* ldlang.c (lang_check): Initialize variables to avoid warnings.
* ldwrite.c (build_link_order): Likewise.
* emultempl/sunos.em (gld${EMULATION_NAME}_find_so): Likewise.
* emultempl/armcoff.em (gld${EMULATION_NAME}_before_allocation):
Remove unused variables.