configure: add test for libudev

Signed-off-by: Tomáš Golembiovský <tgolembi@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
*make libudev optional to avoid breaking existing build/test environments
*disable libudev for --static builds
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

configure

@@ -474,6 +474,7 @@ libxml2=""
 docker="no"
 debug_mutex="no"
 libpmem=""
+libudev="no"
 
 # cross compilers defaults, can be overridden with --cross-cc-ARCH
 cross_cc_aarch64="aarch64-linux-gnu-gcc"
@@ -870,6 +871,7 @@ Linux)
   vhost_vsock="yes"
   QEMU_INCLUDES="-I\$(SRC_PATH)/linux-headers -I$(pwd)/linux-headers $QEMU_INCLUDES"
   supported_os="yes"
+  libudev="yes"
 ;;
 esac
 
@@ -5609,6 +5611,17 @@ if test "$libnfs" != "no" ; then
   fi
 fi
 
+##########################################
+# Do we have libudev
+if test "$libudev" != "no" ; then
+  if $pkg_config libudev && test "$static" != "yes"; then
+    libudev="yes"
+    libudev_libs=$($pkg_config --libs libudev)
+  else
+    libudev="no"
+  fi
+fi
+
 # Now we've finished running tests it's OK to add -Werror to the compiler flags
 if test "$werror" = "yes"; then
     QEMU_CFLAGS="-Werror $QEMU_CFLAGS"
@@ -6033,6 +6046,7 @@ echo "VxHS block device $vxhs"
 echo "capstone          $capstone"
 echo "docker            $docker"
 echo "libpmem support   $libpmem"
+echo "libudev           $libudev"
 
 if test "$sdl_too_old" = "yes"; then
 echo "-> Your SDL version is too old - please upgrade to have SDL support"
@@ -6868,6 +6882,11 @@ if test "$docker" != "no"; then
     echo "HAVE_USER_DOCKER=y" >> $config_host_mak
 fi
 
+if test "$libudev" != "no"; then
+    echo "CONFIG_LIBUDEV=y" >> $config_host_mak
+    echo "LIBUDEV_LIBS=$libudev_libs" >> $config_host_mak
+fi
+
 # use included Linux headers
 if test "$linux" = "yes" ; then
   mkdir -p linux-headers