Flatten the tree of configure scripts.

Collapse all the configure checks to a single configure script in
the root of the source tree. This makes the configure process run
a lot faster, expecially on Windows systems that are slower in general.

autoconf.sh

@@ -9,11 +9,5 @@
 echo "Autoconf in root..."
 autoconf -f
 
-for dir in vpi vvp tgt-vvp tgt-fpga tgt-stub tgt-vhdl libveriuser cadpli
-do
-    echo "Autoconf in $dir..."
-    ( cd ./$dir ; autoconf -f --include=.. )
-done
-
 echo "Precompiling lexor_keyword.gperf"
 gperf -o -i 7 -C -k 1-4,\$ -L ANSI-C -H keyword_hash -N check_identifier -t ./lexor_keyword.gperf > lexor_keyword.cc