bump version to 0.9.19, extra warnings

Bump version to 0.9.19; add some extra warnings (using some new m4 macros)

autogen.sh

@@ -1,2 +1,23 @@
 #!/bin/sh
-echo "please use 'autoreconf -i'"
+# Run this to generate all the initial makefiles, etc.
+
+test -f mu/mu.cc || {
+    echo "*** Run this script from the top-level mu source directory"
+    exit 1
+}
+
+if test -z `which autoreconf`; then
+    echo "*** No autoreconf found, please install it ***"
+    exit 1
+fi
+
+rm -rf autom4te.cache
+autoreconf --force --install --verbose || exit $?
+
+if test -z "$*"; then
+    echo "# Configuring without parameters"
+else
+   echo "# Configure with parameters $*"
+fi
+
+./configure $@