Prior to udev v190, there was no btrfs builtin helper. Installing it on
systems with an older udev will cause problems.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
PKG_CHECK_MODULES(ZLIB, [zlib])
PKG_STATIC(ZLIB_LIBS_STATIC, [zlib])
-UDEVDIR="$(pkg-config udev --variable=udevdir)"
+# udev v190 introduced the btrfs builtin and a udev rule to use it.
+# Our udev rule gives us the friendly dm names but isn't required (or valid)
+# on earlier releases.
+UDEVDIR=
+if pkg-config udev --atleast-version 190; then
+ UDEVDIR="$(pkg-config udev --variable=udevdir)"
+fi
AC_SUBST(UDEVDIR)
dnl lzo library does not provide pkg-config, let use classic way