* elf.c (ET_DYN): Undefine and define again.
(elf_add): Add exe argument, if true and ehdr.e_type is ET_DYN,
return early -1 without closing the descriptor.
(struct phdr_data): Add exe_descriptor.
(phdr_callback): If pd->exe_descriptor is not -1, for very first
call if dlpi_name is NULL just call elf_add with the exe_descriptor,
otherwise backtrace_close the exe_descriptor if not -1. Adjust
call to elf_add.
(backtrace_initialize): Adjust call to elf_add. If it returns
-1, set pd.exe_descriptor to descriptor, otherwise set it to -1.
From-SVN: r205748
