mke2fs: check for a partition table and warn if present

This supercedes the "whole disk" check, since it does a better job and
there are times when it is quite legitimate to want to use the whole
disk.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/configure.in b/configure.in
index e0e6d48..781b6f5 100644
--- a/configure.in
+++ b/configure.in
@@ -1050,6 +1050,7 @@
 	__secure_getenv
 	backtrace
 	blkid_probe_get_topology
+	blkid_probe_enable_partitions
 	chflags
 	fadvise64
 	fallocate