# Check for GNU-style execinfo.h.

dnl Copyright 2012-2017 Free Software Foundation, Inc.
dnl This file is free software; the Free Software Foundation
dnl gives unlimited permission to copy and/or distribute it,
dnl with or without modifications, as long as this notice is preserved.

AC_DEFUN([gl_EXECINFO_H],
[
  AC_CHECK_HEADERS_ONCE([execinfo.h])

  LIB_EXECINFO=''
  EXECINFO_H='execinfo.h'

  if test $ac_cv_header_execinfo_h = yes; then
    gl_saved_libs=$LIBS
      AC_SEARCH_LIBS([backtrace_symbols_fd], [execinfo],
        [test "$ac_cv_search_backtrace_symbols_fd" = "none required" ||
         LIB_EXECINFO=$ac_cv_search_backtrace_symbols_fd])
    LIBS=$gl_saved_libs
    test "$ac_cv_search_backtrace_symbols_fd" = no || EXECINFO_H=''
  fi

  if test -n "$EXECINFO_H"; then
    AC_LIBOBJ([execinfo])
  fi

  AC_SUBST([EXECINFO_H])
  AC_SUBST([LIB_EXECINFO])
  AM_CONDITIONAL([GL_GENERATE_EXECINFO_H], [test -n "$EXECINFO_H"])
])
