error: incomplete definition of type 'struct dl_phdr_info'

[phpstatic.com]

get this build error from Debian:

clang -cc1 version 10.0.1 based upon LLVM 10.0.1 default target x86_64-pc-linux-gnu
ignoring nonexistent directory "/include"
#include "..." search starts here:
#include <...> search starts here:
backtrace
 /usr/local/include
 /usr/lib/llvm-10/lib/clang/10.0.1/include
 /usr/include/x86_64-linux-gnu
 /usr/include
End of search list.
backtrace/elf.c:4812:23: warning: declaration of 'struct dl_phdr_info' will not be visible outside of this function [-Wvisibility]
phdr_callback (struct dl_phdr_info *info, size_t size ATTRIBUTE_UNUSED,
                      ^
backtrace/elf.c:4825:11: error: incomplete definition of type 'struct dl_phdr_info'
  if (info->dlpi_name == NULL || info->dlpi_name[0] == '\0')
      ~~~~^
backtrace/elf.c:4812:23: note: forward declaration of 'struct dl_phdr_info'
phdr_callback (struct dl_phdr_info *info, size_t size ATTRIBUTE_UNUSED,
                      ^
backtrace/elf.c:4825:38: error: incomplete definition of type 'struct dl_phdr_info'
  if (info->dlpi_name == NULL || info->dlpi_name[0] == '\0')
                                 ~~~~^
backtrace/elf.c:4812:23: note: forward declaration of 'struct dl_phdr_info'
phdr_callback (struct dl_phdr_info *info, size_t size ATTRIBUTE_UNUSED,
                      ^
backtrace/elf.c:4841:22: error: incomplete definition of type 'struct dl_phdr_info'
      filename = info->dlpi_name;
                 ~~~~^
backtrace/elf.c:4812:23: note: forward declaration of 'struct dl_phdr_info'
phdr_callback (struct dl_phdr_info *info, size_t size ATTRIBUTE_UNUSED,
                      ^
backtrace/elf.c:4842:40: error: incomplete definition of type 'struct dl_phdr_info'
      descriptor = backtrace_open (info->dlpi_name, pd->error_callback,
                                   ~~~~^
backtrace/elf.c:4812:23: note: forward declaration of 'struct dl_phdr_info'
phdr_callback (struct dl_phdr_info *info, size_t size ATTRIBUTE_UNUSED,
                      ^
backtrace/elf.c:4848:62: error: incomplete definition of type 'struct dl_phdr_info'
  if (elf_add (pd->state, filename, descriptor, NULL, 0, info->dlpi_addr,
                                                         ~~~~^
backtrace/elf.c:4812:23: note: forward declaration of 'struct dl_phdr_info'
phdr_callback (struct dl_phdr_info *info, size_t size ATTRIBUTE_UNUSED,
                      ^
backtrace/elf.c:4892:3: warning: implicit declaration of function 'dl_iterate_phdr' is invalid in C99 [-Wimplicit-function-declaration]
  dl_iterate_phdr (phdr_callback, (void *) &pd);
  ^
2 warnings and 5 errors generated.

[Ian Lance Taylor]

dl_phdr_info should be defined in <link.h>. Can you find out why that is not happening?

[phpstatic.com]

I can see dl_phdr_info from /usr/include/link.h, but not sure why I get this error or how to fix it.

[phpstatic.com]

Add -D_GNU_SOURCE fix it.

[Ian Lance Taylor]

_GNU_SOURCE should be defined by the generated file config.h.