diff --git a/vvp/config.h.in b/vvp/config.h.in
index 57ae4ea40..80718ec52 100644
--- a/vvp/config.h.in
+++ b/vvp/config.h.in
@@ -19,7 +19,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT)
-#ident "$Id: config.h.in,v 1.4 2001/05/05 23:55:46 steve Exp $"
+#ident "$Id: config.h.in,v 1.5 2001/05/11 02:06:14 steve Exp $"
 #endif
 
 # define SIZEOF_UNSIGNED_LONG 0
@@ -27,8 +27,11 @@
 
 # undef HAVE_DLFCN_H
 # undef HAVE_DL_H
+# undef HAVE_GETOPT_H
 # undef HAVE_LIBREADLINE
 
+# undef ENABLE_VVP_DEBUG
+
 # define LU ""
 # define TU ""
 
@@ -36,12 +39,16 @@
 # define MODULE_DIR "."
 #endif
 
-#if defined(HAVE_LIBREADLINE)
+#if defined(HAVE_LIBREADLINE) && defined(ENABLE_VVP_DEBUG)
 # define WITH_DEBUG 1
 #endif
 
 /*
  * $Log: config.h.in,v $
+ * Revision 1.5  2001/05/11 02:06:14  steve
+ *  Add the --enable-vvp-debug option to the configure
+ *  script of vvp, and detect getopt.h.
+ *
  * Revision 1.4  2001/05/05 23:55:46  steve
  *  Add the beginnings of an interactive debugger.
  *
diff --git a/vvp/configure.in b/vvp/configure.in
index d10e22af1..d83c5b3b9 100644
--- a/vvp/configure.in
+++ b/vvp/configure.in
@@ -7,9 +7,16 @@ AC_CHECK_TOOL(STRIP, strip, true)
 
 AC_PROG_INSTALL
 
+AC_ARG_ENABLE(vvp-debug, "interactive debugger for VVP runtime.", AC_DEFINE(ENABLE_VVP_DEBUG))
+
+AC_CHECK_HEADERS(getopt.h)
+
 AC_CHECK_SIZEOF(unsigned long)
 AC_CHECK_SIZEOF(unsigned)
 
+# For the interactive debugger to work, readline must be installed,
+# and that in turn requires termcap. check that the libs really do
+# exist.
 AC_CHECK_LIB(termcap, tputs)
 AC_CHECK_LIB(readline, readline)
 
diff --git a/vvp/main.cc b/vvp/main.cc
index 975eda84d..bf9e025a9 100644
--- a/vvp/main.cc
+++ b/vvp/main.cc
@@ -17,7 +17,7 @@
  *    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  */
 #if !defined(WINNT)
-#ident "$Id: main.cc,v 1.10 2001/05/09 04:23:19 steve Exp $"
+#ident "$Id: main.cc,v 1.11 2001/05/11 02:06:14 steve Exp $"
 #endif
 
 # include  "config.h"
@@ -27,7 +27,9 @@
 # include  "schedule.h"
 # include  "vpi_priv.h"
 # include  <stdio.h>
+#if defined(HAVE_GETOPT_H)
 # include  <getopt.h>
+#endif
 
 
 const char*module_path = MODULE_DIR;
@@ -98,6 +100,10 @@ int main(int argc, char*argv[])
 
 /*
  * $Log: main.cc,v $
+ * Revision 1.11  2001/05/11 02:06:14  steve
+ *  Add the --enable-vvp-debug option to the configure
+ *  script of vvp, and detect getopt.h.
+ *
  * Revision 1.10  2001/05/09 04:23:19  steve
  *  Now that the interactive debugger exists,
  *  there is no use for the output dump.