build: Rename autogen.sh script to bootstrap to conform to GNU guidelines. * bootstrap: renamed from autogen.sh. * autogen.sh: deleted. * build-aux/bootstrap_gnulib: renamed from bootstrap. * build-aux/bootstrap: deleted. * build-aux/bootstrap_gnulib.conf: renamed from bootstrap.conf. * build-aux/bootstrap.conf: deleted. * Makefile.am: add bootstrap and bootstrap_gnulib to EXTRA_DIST. * contrib.txi, HACKING, README.MacOS, README.MinGW, mx-ops, sparse-mx-ops, vx-ops: Replace references to autogen.sh with bootstrap.

copy from autogen.sh
copy to bootstrap
--- a/autogen.sh
+++ b/bootstrap
@@ -1,5 +1,5 @@
 #! /bin/sh
-# autogen.sh
+# bootstrap
 # Run this to generate all the initial makefiles, etc.
 
 set -e
@@ -36,7 +36,7 @@
 
 echo "bootstrapping..."
 
-build-aux/bootstrap "$@"
+build-aux/bootstrap_gnulib "$@"
 
 ## G77 is obsolete, but it is still the first option in the autoconf Fortran
 ## macros.  We should avoid it, because mixing old versions of g77 with modern