* Makefile.in (ALL_TARGET_OBS): Remove object files that require
64-bit CORE_ADDR and BFD support, move them to ...
(ALL_64_TARGET_OBS): ... this new variable.
* configure.ac: Check for --enable-64-bit-bfd option. Only add
64-bit targets with --enable-targets=all if BFD supports 64-bit.
* configure: Regenerate.
* i386-cygwin-tdep.c (i386_cygwin_osabi_sniffer): Do not claim
all elf32-i386 executables, only cygwin core files.