Fix configure.ac and Makefile.in so that they generate pkgIndex.tcl correctly.

FossilOrigin-Name: 3deff25249c59b7fc1b6eb65dda39736955679c6
diff --git a/configure.ac b/configure.ac
index 00ecf45..6a11888 100644
--- a/configure.ac
+++ b/configure.ac
@@ -430,6 +430,7 @@
     AC_SUBST(TCL_STUB_LIB_FILE)
     AC_SUBST(TCL_STUB_LIB_FLAG)
     AC_SUBST(TCL_STUB_LIB_SPEC)
+    AC_SUBST(TCL_SHLIB_SUFFIX)
   fi
 fi
 if test "${use_tcl}" = "no" ; then