diff --git a/aclocal.m4 b/aclocal.m4
index c4475160..365bfa81 100644
--- a/aclocal.m4
+++ b/aclocal.m4
@@ -1,94 +1,6 @@
 dnl ** Additional Autoconf tests for BIRD configure script
 dnl ** (c) 1999 Martin Mares <mj@ucw.cz>
 
-AC_DEFUN([BIRD_CHECK_STRUCT_ALIGN],
-[
-  AC_CACHE_CHECK(
-    [usual alignment of structures],
-    [bird_cv_c_struct_align],
-    [
-      AC_TRY_RUN(
-	[
-	  #include <stdio.h>
-
-	  struct { char x; long int y; } ary[2];
-
-	  int main(void)
-	  {
-	    FILE *f = fopen("conftestresult", "w");
-	    if (!f)
-	      return 10;
-	    fprintf(f, "%d", sizeof(ary)/2);
-	    fclose(f);
-	    exit(0);
-	  }
-	],
-	[bird_cv_c_struct_align=$(cat conftestresult)],
-	[
-	  AC_MSG_RESULT([test program failed])
-	  AC_MSG_ERROR([Cannot determine structure alignment])
-	],
-	[bird_cv_c_struct_align=16]
-      )
-    ]
-  )
-
-  AC_DEFINE_UNQUOTED([CPU_STRUCT_ALIGN],
-    [$bird_cv_c_struct_align],
-    [Usual alignment of structures]
-  )
-])
-
-AC_DEFUN([BIRD_CHECK_TIME_T],
-[
-  AC_CACHE_CHECK(
-    [characteristics of time_t],
-    [bird_cv_type_time_t],
-    [
-      AC_TRY_RUN(
-	[
-	  #include <stdio.h>
-	  #include <sys/time.h>
-	  #include <limits.h>
-
-	  int main(void)
-	  {
-	    FILE *f = fopen("conftestresult", "w");
-	    if (!f)
-	      return 10;
-	    fprintf(f, "%d-bit ", sizeof(time_t)*CHAR_BIT);
-	    if ((time_t) -1 > 0)
-	      fprintf(f, "un");
-	    fprintf(f, "signed");
-	    fclose(f);
-	    exit(0);
-	  }
-	],
-	[bird_cv_type_time_t=$(cat conftestresult)],
-	[
-	  AC_MSG_RESULT([test program failed])
-	  AC_MSG_ERROR([Cannot determine time_t size and signedness.])
-	],
-	[bird_cv_type_time_t="32-bit signed"]
-      )
-    ]
-  )
-
-  case "$bird_cv_type_time_t" in
-    *64-bit*)
-      AC_DEFINE([TIME_T_IS_64BIT], [1],	[Define to 1 if time_t is 64 bit])
-      ;;
-  esac
-
-  case "$bird_cv_type_time_t" in
-    *unsigned*)
-      ;;
-    *)
-      AC_DEFINE([TIME_T_IS_SIGNED], [1], [Define to 1 if time_t is signed])
-      ;;
-  esac
-])
-
 AC_DEFUN([BIRD_CHECK_PTHREADS],
 [
   bird_tmp_cflags="$CFLAGS"
diff --git a/configure.ac b/configure.ac
index aac5679c..7910c196 100644
--- a/configure.ac
+++ b/configure.ac
@@ -320,9 +320,6 @@ AC_C_BIGENDIAN(
   [AC_MSG_ERROR([Cannot determine CPU endianity.])]
 )
 
-BIRD_CHECK_STRUCT_ALIGN
-BIRD_CHECK_TIME_T
-
 if test "$enable_debug" = yes ; then
   AC_DEFINE([DEBUGGING], [1], [Define to 1 if debugging is enabled])
   if test "$enable_memcheck" = yes ; then
diff --git a/lib/birdlib.h b/lib/birdlib.h
index 37337078..d21cdf1f 100644
--- a/lib/birdlib.h
+++ b/lib/birdlib.h
@@ -14,9 +14,12 @@
 
 /* Ugly structure offset handling macros */
 
+struct align_probe { char x; long int y; };
+
 #define OFFSETOF(s, i) ((size_t) &((s *)0)->i)
 #define SKIP_BACK(s, i, p) ((s *)((char *)p - OFFSETOF(s, i)))
 #define BIRD_ALIGN(s, a) (((s)+a-1)&~(a-1))
+#define CPU_STRUCT_ALIGN (sizeof(struct align_probe))
 
 /* Utility macros */
 
diff --git a/sysdep/unix/timer.h b/sysdep/unix/timer.h
index 99d43932..ae5a27e8 100644
--- a/sysdep/unix/timer.h
+++ b/sysdep/unix/timer.h
@@ -77,14 +77,12 @@ bird_clock_t tm_parse_datetime(char *);	/* Convert date to bird_clock_t */
 void
 tm_format_datetime(char *x, struct timeformat *fmt_spec, bird_clock_t t);
 
-#ifdef TIME_T_IS_64BIT
-#define TIME_INFINITY 0x7fffffffffffffff
-#else
-#ifdef TIME_T_IS_SIGNED
-#define TIME_INFINITY 0x7fffffff
-#else
-#define TIME_INFINITY 0xffffffff
-#endif
-#endif
+#define TIME_T_IS_64BIT (sizeof(time_t) == 8)
+#define TIME_T_IS_SIGNED ((time_t) -1 < 0)
+
+#define TIME_INFINITY							\
+  ((time_t) (TIME_T_IS_SIGNED ?						\
+	     (TIME_T_IS_64BIT ? 0x7fffffffffffffff : 0x7fffffff):	\
+	     (TIME_T_IS_64BIT ? 0xffffffffffffffff : 0xffffffff)))
 
 #endif