From: Jeff Mahoney <jeffm@suse.com>
Subject: btrfs-progs: make PKG_CHECK_VAR optional
Patch-upstream: Never, SLE11-specific

SLE11 has an old enough pkg-config that PKG_CHECK_VAR doesn't exist.

We can skip checking it because SLE11 doesn't have systemd's btrfs udev
rules either and 'make install' does the right thing if UDEVDIR is empty.
---

 configure.ac |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 4af7474..64b1c7a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -124,7 +124,10 @@ PKG_STATIC(UUID_LIBS_STATIC, [uuid])
 PKG_CHECK_MODULES(ZLIB, [zlib])
 PKG_STATIC(ZLIB_LIBS_STATIC, [zlib])
 
-PKG_CHECK_VAR([UDEVDIR], [udev], [udevdir])
+UDEVDIR=
+m4_ifdef([PKG_CHECK_VAR],
+[PKG_CHECK_VAR([UDEVDIR], [udev], [udevdir])])
+AC_SUBST(UDEVDIR)
 
 dnl lzo library does not provide pkg-config, let use classic way
 AC_CHECK_LIB([lzo2], [lzo_version], [