- Issue #17031: Fix running regen in cross builds.
diff --git a/configure.ac b/configure.ac
index 75eb5da..5526f99 100644
--- a/configure.ac
+++ b/configure.ac
@@ -50,6 +50,8 @@
 AC_CONFIG_HEADER(pyconfig.h)
 
 AC_CANONICAL_HOST
+AC_SUBST(build)
+AC_SUBST(host)
 
 if test "$cross_compiling" = yes; then
     AC_MSG_CHECKING([for python interpreter for cross build])