* netbsd-core.c (netbsd_core_file_p): Use bfd_make_section_anyway
rather than doing our own section handling. Clean up after errors
with bfd_release and bfd_section_list_clear. Handle unexpected
flags.
* aoutf1.h (sunos4_core_file_p): Likewise.
* aix386-core.c (aix386_core_file_p): Likewise.
* cisco-core.c (cisco_core_file_validate): Likewise.
* ptrace-core.c (ptrace_unix_core_file_p): Likewise.
* trad-core.c (trad_unix_core_file_p): Likewise.
* hppabsd-core.c (hppabsd_core_core_file_p): Clean up after errors
with bfd_release and bfd_section_list_clear.
* hpux-core.c (hpux_core_core_file_p): Likewise.
* irix-core.c (irix_core_core_file_p): Likewise.
* lynx-core.c (lynx_core_file_p): Likewise.
* osf-core.c (osf_core_core_file_p): Likewise.
* rs6000-core.c (rs6000coff_core_p): Likewise.
* sco5-core.c (sco5_core_file_p): Likewise.