Have autoreconf deal with initializing GNU build system

Let the autoreconf tool handle the sequencing of tool calls.

The autoreconf tool has been dealing with calling tools like
aclocal, libtoolize, etc. quite well for about the last 20 years.

This keeps the "bootstrap" script around to keep the old way
of calling bootstrap working, i.e. maintain compatibility with the
existing workflows.

src/bootstrap

@@ -1,5 +1,6 @@
 #! /bin/sh
 
+: ${AUTORECONF="autoreconf${AC_VER}"}
 : ${AUTOHEADER="autoheader${AC_VER}"}
 : ${AUTOCONF="autoconf${AC_VER}"}
 : ${ACLOCAL="aclocal${AM_VER}"}
@@ -17,9 +18,6 @@ rm -rf autom4te.cache
 # probe for that
 LIBTOOLIZE=libtoolize
 glibtoolize --version > /dev/null 2>&1 && LIBTOOLIZE=glibtoolize
-${LIBTOOLIZE}
+export LIBTOOLIZE
 
-${ACLOCAL}
-${AUTOHEADER}
-${AUTOCONF}
-${AUTOMAKE} -a -c
+${AUTORECONF} -i