--- a/configure.ac	2011-05-22 14:59:45.801746472 +0100
+++ b/configure.ac	2011-05-22 15:02:59.437159981 +0100
@@ -14,17 +14,14 @@ AC_HEADER_STDC
 
 dnl ------ libtool versioning -----------------------------------------------
 
-LT_CURRENT=0
-LT_REVISION=1
-LT_AGE=0
-AC_SUBST(LT_CURRENT)
-AC_SUBST(LT_REVISION)
-AC_SUBST(LT_AGE)
+m4_define(LT_CURRENT, 0)
+m4_define(LT_REVISION, 1)
+m4_define(LT_AGE, 0)
 
-LT_VERSION_INFO="$LT_CURRENT:$LT_REVISION:$LT_AGE"
+LT_VERSION_INFO="LT_CURRENT():LT_REVISION():LT_AGE()"
 AC_SUBST(LT_VERSION_INFO)
 
-LT_CURRENT_MINUS_AGE=`expr $LT_CURRENT - $LT_AGE`
+LT_CURRENT_MINUS_AGE="m4_eval(LT_CURRENT() - LT_AGE())"
 AC_SUBST(LT_CURRENT_MINUS_AGE)
 
 dnl ------ Check for X Stuff ------------------------------------------------