btrfs-progs: autogen: Make build success in CentOS 6 and 7

btrfs-progs build failed in CentOS 6 and 7:
 #./autogen.sh
 ...
 configure.ac:131: error: possibly undefined macro: PKG_CHECK_VAR
      If this token and others are legitimate, please use m4_pattern_allow.
      See the Autoconf documentation.
 ...

Seems PKG_CHECK_VAR is new in pkgconfig 0.28 (24-Jan-2013):
http://redmine.audacious-media-player.org/boards/1/topics/736

And the max available version for CentOS 7 in yum-repo and
rpmfind.net is: pkgconfig-0.27.1-4.el7
http://rpmfind.net/linux/rpm2html/search.php?query=pkgconfig&submit=Search+...&system=centos&arch=

I updated my pkgconfig to 0.30, but still failed at above error.
(Maybe it is my setting problem)

To make user in centos 6 and 7 building btrfs-progs without
more changes, we can avoid using PKG_CHECK_VAR in following
way found in:
https://github.com/audacious-media-player/audacious-plugins/commit/f95ab6f939ecf0d9232b3165f9241d2ea9676b9e

Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/configure.ac b/configure.ac
index 68a3701..6b68c09 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -124,7 +124,8 @@ PKG_STATIC(UUID_LIBS_STATIC, [uuid])
 PKG_CHECK_MODULES(ZLIB, [zlib])
 PKG_STATIC(ZLIB_LIBS_STATIC, [zlib])
 
-PKG_CHECK_VAR([UDEVDIR], [udev], [udevdir])
+UDEVDIR="$(pkg-config udev --variable=udevdir)"
+AC_SUBST(UDEVDIR)
 
 dnl lzo library does not provide pkg-config, let use classic way
 AC_CHECK_LIB([lzo2], [lzo_version], [