preadv/preadv01.c: add new testcase

Test preadv(2) with some basic functions.
Preadv(2) should succeed to read the expected content of data
and the file offset is not changed after reading the file.

Signed-off-by: Xiao Yang <yangx.jy@cn.fujitsu.com>
Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
diff --git a/configure.ac b/configure.ac
index cc89273..609de8f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -181,5 +181,6 @@
 LTP_CHECK_IF_LINK
 LTP_CHECK_KCMP
 LTP_CHECK_KCMP_TYPE
+LTP_CHECK_PREADV
 
 AC_OUTPUT