Don't make it possible to define HAVE_HAL but not enable it in automake

* configure.in: With the previous logic, if libhal_get_all_devices
  function was not found, HAVE_HAL would be defined for the preprocessor
  but it wouldn't be enabled in automake conditionals, causing the final
  link to fail with missing references to HAL entries.

configure.in

@@ -1723,9 +1723,6 @@ if test "x$with_hal" = "xyes" -o "x$with_hal" = "xcheck"; then
     fi
   ])
   if test "x$with_hal" = "xyes" ; then
-    AC_DEFINE_UNQUOTED([HAVE_HAL], 1,
-      [use HAL for host device enumeration])
-
     old_CFLAGS=$CFLAGS
     old_LDFLAGS=$LDFLAGS
     CFLAGS="$CFLAGS $HAL_CFLAGS"
@@ -1735,6 +1732,10 @@ if test "x$with_hal" = "xyes" -o "x$with_hal" = "xcheck"; then
     CFLAGS="$old_CFLAGS"
     LDFLAGS="$old_LDFLAGS"
   fi
+  if test "x$with_hal" = "xyes" ; then
+    AC_DEFINE_UNQUOTED([HAVE_HAL], 1,
+      [use HAL for host device enumeration])
+  fi
 fi
 AM_CONDITIONAL([HAVE_HAL], [test "x$with_hal" = "xyes"])
 AC_SUBST([HAL_CFLAGS])