[PATCH xserver] Move dtrace out of os,dix

[Mihail Konev]

Tiny portability addition:

diff --git a/configure.ac b/configure.ac
index efe38883125b..9310160c8b7a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -73,6 +73,7 @@ dnl version-config.h covers the version numbers so they can be bumped without
 dnl forcing an entire recompile.x
 AC_CONFIG_HEADERS(include/version-config.h)
 
+AM_PROG_AR
 AM_PROG_AS
 AC_PROG_LN_S
 LT_PREREQ([2.2])