configure: assume that systems assert() is functional if available

configure.ac

@@ -2352,20 +2352,8 @@ AS_VAR_IF([[enable_asserts]], [["yes"]],
                      [[mhd_cv_sys_assert_avail='no']])
      ]
    )
-   AS_VAR_IF([[mhd_cv_sys_assert_avail]], [["yes"]],
-     [
-      AC_CACHE_CHECK([[whether system assert() is usable]], [mhd_cv_sys_assert_use],
-        [
-         AC_RUN_IFELSE([AC_LANG_SOURCE([[$mhd_assert_test_prg]])],
-                       [[mhd_cv_sys_assert_use='no']],
-                       [[mhd_cv_sys_assert_use='yes']],
-                       [[mhd_cv_sys_assert_use='assuming yes']])
-        ]
-      )
-      AS_VAR_IF([[mhd_cv_sys_assert_use]], [["no"]], [],
-        [AC_DEFINE([[HAVE_ASSERT]], [[1]], [Define if you have usable assert() and assert.h])])
-     ]
-   )
+   AS_VAR_IF([[mhd_cv_sys_assert_avail]], [["no"]], [],
+     [AC_DEFINE([[HAVE_ASSERT]], [[1]], [Define if you have usable assert() and assert.h])])
    AS_UNSET([mhd_assert_test_prg])
   ],
   [AC_DEFINE([[NDEBUG]], [[1]], [Define to disable usage of debug asserts.])]