fix musl build

Patch inspired by
https://github.com/kraj/meta-musl/blob/master/recipes-core/util-linux/util-linux-2.25/0001-switch_root-use-typeof-instead-of-__SWORD_TYPE-for-s.patch

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>

diff -uNr ecryptfs-utils-109.org/src/utils/mount.ecryptfs_private.c ecryptfs-utils-109/src/utils/mount.ecryptfs_private.c
--- ecryptfs-utils-109.org/src/utils/mount.ecryptfs_private.c	2016-01-22 17:04:52.000000000 +0100
+++ ecryptfs-utils-109/src/utils/mount.ecryptfs_private.c	2016-01-24 16:52:37.000000000 +0100
@@ -224,6 +224,7 @@
 
 static int check_cwd_f_type()
 {
+	struct statfs buf;
 	/**
 	 * This is *not* a list of compatible lower filesystems list for
 	 * eCryptfs. This is a list of filesystems that we reasonably expect to
@@ -235,7 +236,7 @@
 	 * deceive other programs with a crafted /proc/self/*. See
 	 * https://launchpad.net/bugs/1530566 for more details.
 	 */
-	__SWORD_TYPE f_type_whitelist[] = {
+	typeof(buf.f_type) f_type_whitelist[] = {
 		0x61756673 /* AUFS_SUPER_MAGIC */,
 		0x9123683E /* BTRFS_SUPER_MAGIC */,
 		0x00C36400 /* CEPH_SUPER_MAGIC */,
@@ -259,7 +260,6 @@
 		0x58465342 /* XFS_SB_MAGIC */,
 		0x2FC12FC1 /* ZFS_SUPER_MAGIC */,
 	};
-	struct statfs buf;
 	size_t i, whitelist_len;
 
 	if (statfs(".", &buf) != 0) {