build: fix detection of netcf linked with libnl1

Commit 9298bfbcb introduced code to detect if netcf is linked with
libnl1, and to prefer libnl1 over libnl3 when this is the case.
This behaviour can be disabled by setting LIBNL_CFLAGS to any value,
including the empty string.
However, configure.ac sets LIBNL_CFLAGS to "" before attempting
libnl detection, so the libnl1 detection code is always disabled.
This caused issues on my f17 system where netcf is linked with libnl1
but libvirt got built with libnl3.

This commit removes the setting of the LIBNL_* variables to "" as
this does not appear to be needed. After this change, libnl1 is
used when building libvirt on my f17 system.
(cherry picked from commit f6c295156672fe15b32d2baddb68957bb7bddd8e)

diff --git a/configure.ac b/configure.ac
index 1d71e161e1105b72762b77de4d81f9ab0a395b69..9e7deba8179083e5a013cbbbf496f8fe9feec75b 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -2647,10 +2647,6 @@ AM_CONDITIONAL([WITH_VIRTUALPORT], [test "$with_virtualport" = "yes"])
 
 dnl netlink library
 
-LIBNL_ROUTE3_CFLAGS=""
-LIBNL_ROUTE3_LIBS=""
-LIBNL_CFLAGS=""
-LIBNL_LIBS=""
 have_libnl=no
 
 if test "$with_linux" = "yes"; then