Supporting tcl 8.6

diff --git a/config/tcl.m4 b/config/tcl.m4
new file mode 100644
index e886057..a9fe7ba
*** a/config/tcl.m4
--- b/config/tcl.m4
***************
*** 4,10 ****
  
  
  AC_DEFUN([PGAC_PATH_TCLSH],
! [AC_PATH_PROGS(TCLSH, [tclsh tcl tclsh8.5 tclsh85 tclsh8.4 tclsh84 tclsh8.3 tclsh83])
  if test x"$TCLSH" = x""; then
    AC_MSG_ERROR([Tcl shell not found])
  fi
--- 4,10 ----
  
  
  AC_DEFUN([PGAC_PATH_TCLSH],
! [AC_PATH_PROGS(TCLSH, [tclsh tcl tclsh8.6 tclsh86 tclsh8.5 tclsh85 tclsh8.4 tclsh84 tclsh8.3 tclsh83])
  if test x"$TCLSH" = x""; then
    AC_MSG_ERROR([Tcl shell not found])
  fi
diff --git a/configure b/configure
new file mode 100755
index 9953389..5154ace
*** a/configure
--- b/configure
*************** fi
*** 13891,13897 ****
  
  # Check for Tcl configuration script tclConfig.sh
  if test "$with_tcl" = yes; then
!     for ac_prog in tclsh tcl tclsh8.5 tclsh85 tclsh8.4 tclsh84 tclsh8.3 tclsh83
  do
    # Extract the first word of "$ac_prog", so it can be a program name with args.
  set dummy $ac_prog; ac_word=$2
--- 13891,13897 ----
  
  # Check for Tcl configuration script tclConfig.sh
  if test "$with_tcl" = yes; then
!     for ac_prog in tclsh tcl tclsh8.6 tclsh86 tclsh8.5 tclsh85 tclsh8.4 tclsh84 tclsh8.3 tclsh83
  do
    # Extract the first word of "$ac_prog", so it can be a program name with args.
  set dummy $ac_prog; ac_word=$2