some cleanup checking for xmllint and xsltproc in configure.in, fixed make

* configure.in doc/Makefile.am xstc/Makefile.am: some cleanup
  checking for xmllint and xsltproc in configure.in, fixed
  make dist w.r.t. the new xstc subdir.
* doc/*: rebuilt
Daniel
diff --git a/configure.in b/configure.in
index 1db9512..24d2619 100644
--- a/configure.in
+++ b/configure.in
@@ -40,6 +40,8 @@
 AC_PATH_PROG(MV, mv, /bin/mv)
 AC_PATH_PROG(TAR, tar, /bin/tar)
 AC_PATH_PROG(PERL, perl, /usr/bin/perl)
+AC_PATH_PROG(XMLLINT, xmllint, /usr/bin/xsltproc)
+AC_PATH_PROG(XSLTPROC, xsltproc, /usr/bin/xsltproc)
 
 dnl Make sure we have an ANSI compiler
 AM_C_PROTOTYPES