Use modern autoconf-archive macro to ensure @CC_FOR_BUILD@ and such gets
replaced in Makefiles.
--- a/configure.in
+++ b/configure.in
@@ -9,7 +9,7 @@ AC_PROG_CC
 AC_PROG_GCC_TRADITIONAL
 AC_PROG_INSTALL
 AC_PROG_LN_S
-AX_CC_FOR_BUILD
+AX_PROG_CC_FOR_BUILD
 
 AC_PATH_PROG(INSTALL_INFO, install-info, "")