use automake and libtool

This commits replaces the handwritten makefile with automake+libtool.
There is some hackery needed for the LD_PRELOAD shared library,
but apart from that there is nothing special and it is a large gain in
portability and standardization.

The spec file is modified as little as is needed to properly build
the RPMs.

autogen.sh

@@ -1,13 +1,13 @@
 #!/bin/sh
 
 rm -rf autom4te.cache
-rm -f configure config.h.in libiscsi.pc
-
-IPATHS="-I ./include -I ../include"
-
-autoheader $IPATHS || exit 1
-autoconf $IPATHS || exit 1
+rm -f depcomp aclocal.m4 missing config.guess config.sub install-sh
+rm -f configure config.h.in config.h.in~ m4/libtool.m4 m4/lt*.m4 Makefile.in
 
+autoreconf -fvi
+(cd m4 && for i in libtool.m4 lt*.m4; do
+  echo /$i
+done) > m4/.gitignore
 rm -rf autom4te.cache
 
 echo "Now run ./configure and then make."