diff --git a/configure.in b/configure.in
index 9f39d6c..285085a 100644
--- a/configure.in
+++ b/configure.in
@@ -251,6 +251,8 @@ AM_CONDITIONAL(MINGW32, test "$MINGW32" = "yes")
 AM_CONDITIONAL(MAC, test "$MAC" = "yes")
 
 # export macros
+RPMBUILD=${BUILD_NUMBER}
+AC_SUBST(RPMBUILD)
 SRCDIR=${srcdir}
 AC_SUBST(SRCDIR)
 AC_SUBST(SRC_DIR)