dnl Copyright (C) 2000-2026 Free Software Foundation, Inc.dnldnl GCC is free software; you can redistribute it and/or modifydnl it under the terms of the GNU General Public License as published bydnl the Free Software Foundation; either version 3, or (at your option)dnl any later version.dnldnl GCC is distributed in the hope that it will be useful,dnl but WITHOUT ANY WARRANTY; without even the implied warranty ofdnl MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See thednl GNU General Public License for more details.dnldnl You should have received a copy of the GNU General Public Licensednl along with GCC; see the file COPYING3.  If not seednl <http://www.gnu.org/licenses/>. dnl See whether strncmp reads past the end of its string parameters.dnl On some versions of SunOS4 at least, strncmp reads a word at a timednl but erroneously reads past the end of strings.  This can causednl a SEGV in some cases.AC_DEFUN([libiberty_AC_FUNC_STRNCMP],[AC_REQUIRE([GCC_AC_FUNC_MMAP])AC_CACHE_CHECK([for working strncmp], ac_cv_func_strncmp_works,[AC_TRY_RUN([/* Test by Jim Wilson and Kaveh Ghazi.   Check whether strncmp reads past the end of its string parameters. */#include <stdlib.h>#include <string.h>#include <sys/types.h> #ifdef HAVE_FCNTL_H#include <fcntl.h>#endif #ifdef HAVE_SYS_MMAN_H#include <sys/mman.h>#endif #ifndef MAP_ANON#ifdef MAP_ANONYMOUS#define MAP_ANON MAP_ANONYMOUS#else#define MAP_ANON MAP_FILE#endif#endif #ifndef MAP_FILE#define MAP_FILE 0#endif#ifndef O_RDONLY#define O_RDONLY 0#endif #define MAP_LEN 0x10000 intmain (void){#if defined(HAVE_MMAP) || defined(HAVE_MMAP_ANYWHERE)  char *p;  int dev_zero;   dev_zero = open ("/dev/zero", O_RDONLY);  if (dev_zero < 0)    exit (1);   p = (char *) mmap (0, MAP_LEN, PROT_READ|PROT_WRITE,		     MAP_ANON|MAP_PRIVATE, dev_zero, 0);  if (p == (char *)-1)    p = (char *) mmap (0, MAP_LEN, PROT_READ|PROT_WRITE,		       MAP_ANON|MAP_PRIVATE, -1, 0);  if (p == (char *)-1)    exit (2);  else    {      char *string = "__si_type_info";      char *q = (char *) p + MAP_LEN - strlen (string) - 2;      char *r = (char *) p + 0xe;       strcpy (q, string);      strcpy (r, string);      strncmp (r, q, 14);    }#endif /* HAVE_MMAP || HAVE_MMAP_ANYWHERE */  exit (0);}], ac_cv_func_strncmp_works=yes, ac_cv_func_strncmp_works=no,  ac_cv_func_strncmp_works=yes)rm -f core core.* *.core])if test $ac_cv_func_strncmp_works = no ; then  AC_LIBOBJ([strncmp])fi]) dnl See if errno must be declared even when <errno.h> is included.AC_DEFUN([libiberty_AC_DECLARE_ERRNO],[AC_CACHE_CHECK(whether errno must be declared, libiberty_cv_declare_errno,[AC_TRY_COMPILE([#include <errno.h>],[int x = errno;],libiberty_cv_declare_errno=no,libiberty_cv_declare_errno=yes)])if test $libiberty_cv_declare_errno = yesthen AC_DEFINE(NEED_DECLARATION_ERRNO, 1,  [Define if errno must be declared even when <errno.h> is included.])fi]) dnl See whether we need a declaration for a function.AC_DEFUN([libiberty_NEED_DECLARATION],[AC_MSG_CHECKING([whether $1 must be declared])AC_CACHE_VAL(libiberty_cv_decl_needed_$1,[AC_TRY_COMPILE([#include "confdefs.h"#include <stdio.h>#ifdef HAVE_STRING_H#include <string.h>#else#ifdef HAVE_STRINGS_H#include <strings.h>#endif#endif#ifdef HAVE_STDLIB_H#include <stdlib.h>#endif#ifdef HAVE_UNISTD_H#include <unistd.h>#endif],[char *(*pfn) = (char *(*)) $1],libiberty_cv_decl_needed_$1=no, libiberty_cv_decl_needed_$1=yes)])AC_MSG_RESULT($libiberty_cv_decl_needed_$1)if test $libiberty_cv_decl_needed_$1 = yes; then  AC_DEFINE([NEED_DECLARATION_]translit($1, [a-z], [A-Z]), 1,            [Define if $1 is not declared in system header files.])fi])dnl # We always want a C version of alloca() compiled into libiberty,# because native-compiler support for the real alloca is so !@#$%# unreliable that GCC has decided to use it only when being compiled# by GCC.  This is the part of AC_FUNC_ALLOCA that calculates the# information alloca.c needs.AC_DEFUN([libiberty_AC_FUNC_C_ALLOCA],[AC_CACHE_CHECK(whether alloca needs Cray hooks, ac_cv_os_cray,[AC_EGREP_CPP(webecray,[#if defined(CRAY) && ! defined(CRAY2)webecray#elsewenotbecray#endif], ac_cv_os_cray=yes, ac_cv_os_cray=no)])if test $ac_cv_os_cray = yes; then  for ac_func in _getb67 GETB67 getb67; do    AC_CHECK_FUNC($ac_func,      [AC_DEFINE_UNQUOTED(CRAY_STACKSEG_END, $ac_func,  [Define to one of _getb67, GETB67, getb67 for Cray-2 and Cray-YMP   systems. This function is required for alloca.c support on those   systems.])  break])  donefi AC_CACHE_CHECK(stack direction for C alloca, ac_cv_c_stack_direction,[AC_TRY_RUN([#include <stdlib.h> intfind_stack_direction (void){  static char *addr = 0;  auto char dummy;  if (addr == 0)    {      addr = &dummy;      return find_stack_direction ();    }  else    return (&dummy > addr) ? 1 : -1;} intmain (void){  exit (find_stack_direction() < 0);}],  ac_cv_c_stack_direction=1,  ac_cv_c_stack_direction=-1,  ac_cv_c_stack_direction=0)])AC_DEFINE_UNQUOTED(STACK_DIRECTION, $ac_cv_c_stack_direction,  [Define if you know the direction of stack growth for your system;   otherwise it will be automatically deduced at run-time.        STACK_DIRECTION > 0 => grows toward higher addresses        STACK_DIRECTION < 0 => grows toward lower addresses        STACK_DIRECTION = 0 => direction of growth unknown])])