diff -crN a/config/c-compiler.m4 b/config/c-compiler.m4
*** a/config/c-compiler.m4	2016-02-09 06:17:25.000000000 +0900
--- b/config/c-compiler.m4	2025-08-15 13:46:42.000000000 +0900
***************
*** 84,91 ****
      return 0;
    return 1;
  }
  main() {
!   exit(! does_int64_work());
  }],
  [Ac_cachevar=yes],
  [Ac_cachevar=no],
--- 84,93 ----
      return 0;
    return 1;
  }
+ 
+ int
  main() {
!   return (! does_int64_work());
  }],
  [Ac_cachevar=yes],
  [Ac_cachevar=no],
diff -crN a/config/c-library.m4 b/config/c-library.m4
*** a/config/c-library.m4	2016-02-09 06:17:25.000000000 +0900
--- b/config/c-library.m4	2025-08-15 13:47:21.000000000 +0900
***************
*** 250,257 ****
      return 0;			/* either multiply or snprintf is busted */
    return 1;
  }
  main() {
!   exit(! does_int64_snprintf_work());
  }],
  [pgac_cv_snprintf_long_long_int_format=$pgac_format; break],
  [],
--- 250,259 ----
      return 0;			/* either multiply or snprintf is busted */
    return 1;
  }
+ 
+ int
  main() {
!   return (! does_int64_snprintf_work());
  }],
  [pgac_cv_snprintf_long_long_int_format=$pgac_format; break],
  [],
diff -crN a/configure b/configure
*** a/configure	2016-02-09 06:17:25.000000000 +0900
--- b/configure	2025-08-15 13:46:02.000000000 +0900
***************
*** 24846,24853 ****
      return 0;
    return 1;
  }
  main() {
!   exit(! does_int64_work());
  }
  _ACEOF
  rm -f conftest$ac_exeext
--- 24846,24855 ----
      return 0;
    return 1;
  }
+ 
+ int
  main() {
!   return (! does_int64_work());
  }
  _ACEOF
  rm -f conftest$ac_exeext
***************
*** 24985,24992 ****
      return 0;
    return 1;
  }
  main() {
!   exit(! does_int64_work());
  }
  _ACEOF
  rm -f conftest$ac_exeext
--- 24987,24996 ----
      return 0;
    return 1;
  }
+ 
+ int
  main() {
!   return (! does_int64_work());
  }
  _ACEOF
  rm -f conftest$ac_exeext
***************
*** 25150,25157 ****
      return 0;			/* either multiply or snprintf is busted */
    return 1;
  }
  main() {
!   exit(! does_int64_snprintf_work());
  }
  _ACEOF
  rm -f conftest$ac_exeext
--- 25154,25163 ----
      return 0;			/* either multiply or snprintf is busted */
    return 1;
  }
+ 
+ int
  main() {
!   return (! does_int64_snprintf_work());
  }
  _ACEOF
  rm -f conftest$ac_exeext