Remove some unused macros from 'configure'.

Remove some unused macros from 'configure'.

* configure.ac (HAVE_SOUNDCARD_H, HAVE_LINUX_VERSION_H, HAVE_SPEED_T)
(HAVE_GNUTLS_CALLBACK_CERTIFICATE_VERIFY)
(HAVE_GNUTLS_CERTIFICATE_SET_VERIFY_FUNCTION, HAVE_UTIMES)
(HAVE_LIBHESIOD, HAVE_LIBRESOLV, HAVE_LIBCOM_ERR, HAVE_LIBCRYPTO)
(HAVE_LIBK5CRYPTO, HAVE_LIBKRB5, HAVE_LIBDES425, HAVE_LIBDES)
(HAVE_LIBKRB4, HAVE_LIBKRB, HAVE_DES_H, HAVE_KERBEROSIV_DES_H)
(HAVE_DEV_PTMX, DEVICE_SEP, USG5):
Remove these macros, as they are not used.
(sys_siglist): Remove macro; src/sysdep.c now does this.
* src/sysdep.c (sys_siglist) [HAVE_DECL___SYS_SIGLIST]:
Define to __sys_siglist.