(AM_INIT_AUTOMAKE): Use tar-ustar option. Raise version requirement to 1.9

configure.ac

@@ -23,7 +23,7 @@ AC_CONFIG_SRCDIR([src/tar.c])
 AC_CONFIG_AUX_DIR([build-aux])
 AC_CONFIG_HEADERS([config.h:config.hin])
 AC_PREREQ([2.59])
-AM_INIT_AUTOMAKE([1.8 gnits dist-bzip2 dist-shar std-options])
+AM_INIT_AUTOMAKE([1.9 gnits tar-ustar dist-bzip2 dist-shar std-options])
 
 gl_USE_SYSTEM_EXTENSIONS
 AC_PROG_CC