Update autoconf to 2.71

aclocal.m4

-# FP_DECL_ALTZONE
-# ---------------
-# Defines HAVE_DECL_ALTZONE to 1 if declared, 0 otherwise.
-#
-# Used by base package.
-AC_DEFUN([FP_DECL_ALTZONE],
-[AC_REQUIRE([AC_HEADER_TIME])dnl
-AC_CHECK_HEADERS([sys/time.h])
-AC_CHECK_DECLS([altzone], [], [],[#if TIME_WITH_SYS_TIME
-# include <sys/time.h>
-# include <time.h>
-#else
-# if HAVE_SYS_TIME_H
-#  include <sys/time.h>
-# else
-#  include <time.h>
-# endif
-#endif])
-])# FP_DECL_ALTZONE
+# FP_DECL_ALTZONE
+# ---------------
+# Defines HAVE_DECL_ALTZONE to 1 if declared, 0 otherwise.
+#
+# Used by base package.
+AC_DEFUN([FP_DECL_ALTZONE],
+[
+  AC_CHECK_HEADERS_ONCE([sys/time.h])
+
+  AC_CHECK_HEADERS([sys/time.h])
+  AC_CHECK_DECLS([altzone], [], [],[
+  #if HAVE_SYS_TIME_H
+  #include <sys/time.h>
+  #endif
+  #include <time.h>
+  ])
+])# FP_DECL_ALTZONE