From: Jan Wieck <jwieck@debis.com>

    A few minutes ago I sent down the PL/Tcl  directory  to  this
    list.  Look at it and reuse anything that might help to build
    PL/perl.  I really hope that PL/perl and PL/Tcl appear in the
    6.3 distribution. I'll do whatever I can to make this happen.

src/pl/tcl/INSTALL

+Installation instructions for PL/Tcl
+
+1.  Build the pltcl shared library
+
+    The Makefile for the pltcl shared library assumes the sources
+    for PostgreSQL are in /usr/local/src/postgresql-6.2.1/src. Edit
+    if not.
+
+    The Makefile depends on the tclConfig.sh file that get's installed
+    with Tcl. This should either be in /usr/lib or in /usr/local/lib.
+    If it is in a different place, edit mkMakefile.tcldefs or make a
+    symbolic link to it here.
+
+    Type make and the shared library should get built.
+
+2.  Now create the PL/Tcl language in PostgreSQL
+
+    Since the pg_language system catalog is private to each database,
+    the new language can be created only for individual databases,
+    or in the template1 database. In the latter case, it is
+    automatically available in all newly created databases.
+
+    The commands to create the new language are:
+
+        create function pltcl_call_handler () returns opaque
+    		as 'path-to-pltcl-shared-lib'
+    		language 'C';
+
+	create trusted procedural language 'pltcl'
+		handler pltcl_call_handler
+		lancompiler 'PL/Tcl';
+
+    The trusted keyword on create procedural language tells PostgreSQL,
+    that all users (not only those with superuser privilege) are
+    permitted to create functions with LANGUAGE 'pltcl'. This is
+    absolutely safe, because there is nothing a normal user can do
+    with PL/Tcl, to get around access restrictions he/she has.
+
+3.  Use PL/Tcl
+
+    Read pltcl_guide.txt to learn how to write functions and
+    trigger procedures in PL/Tcl.
+

src/pl/tcl/Makefile

+#-------------------------------------------------------------------------
+#
+# Makefile
+#    Makefile for the pltcl shared object
+#
+# IDENTIFICATION
+#    $Header: /cvsroot/pgsql/src/pl/tcl/Makefile,v 1.1 1998/02/11 14:07:55 scrappy Exp $
+#
+#-------------------------------------------------------------------------
+
+#
+# Tell make where the postgresql sources live
+#
+SRCDIR= ../../../src
+include $(SRCDIR)/Makefile.global
+
+
+#
+# Include definitions from the tclConfig.sh file
+#
+include Makefile.tcldefs
+
+
+#
+# Uncomment the following to force a specific version of the
+# Tcl shared library to be used.
+#
+#TCL_LIB_SPEC=-L/usr/lib -ltcl8.0
+
+
+#
+# Change following to how shared library that contain
+# correct references to libtcl must get built on your system.
+# Since these definitions come from the tclConfig.sh script,
+# they should work if the shared build of tcl was successful
+# on this system.
+#
+%$(TCL_SHLIB_SUFFIX):	%.o
+	$(TCL_SHLIB_LD) -o $@ $< $(TCL_SHLIB_LD_LIBS) $(TCL_LIB_SPEC) $(TCL_LIBS)
+
+
+#
+# Uncomment the following to enable the unknown command lookup
+# on the first of all calls to the call handler. See the doc
+# in the modules directory about details.
+#
+#CFLAGS+= -DPLTCL_UNKNOWN_SUPPORT
+
+
+CC = $(TCL_CC)
+CFLAGS+= -I$(LIBPQDIR) -I$(SRCDIR)/include $(TCL_SHLIB_CFLAGS)
+
+# For fmgr.h
+CFLAGS+= -I$(SRCDIR)/backend
+
+CFLAGS+= $(TCL_DEFS)
+
+LDADD+= -L$(LIBPQDIR) -lpq
+        
+#
+# DLOBJS is the dynamically-loaded object file.
+#
+DLOBJS= pltcl$(DLSUFFIX)
+
+INFILES= $(DLOBJS) 
+
+#
+# plus exports files
+#
+ifdef EXPSUFF
+INFILES+= $(DLOBJS:.o=$(EXPSUFF))
+endif
+
+#
+# Build the shared lib
+#
+all: $(INFILES)
+
+Makefile.tcldefs:
+	./mkMakefile.tcldefs
+
+#
+# Clean 
+#
+clean:
+	rm -f $(INFILES)
+	rm -f Makefile.tcldefs
+
+install: all
+	$(INSTALL) $(INSTL_LIB_OPTS) $(DLOBJS) $(DESTDIR)$(LIBDIR)/$(DLOBJS)
+

src/pl/tcl/license.terms

+    This software is copyrighted by Jan Wieck - Hamburg.
+
+    The  following  terms  apply to all files associated with the
+    software unless explicitly disclaimed in individual files.
+
+    The author hereby grants permission  to  use,  copy,  modify,
+    distribute,  and  license this software and its documentation
+    for any purpose, provided that existing copyright notices are
+    retained  in  all  copies  and  that  this notice is included
+    verbatim in any distributions. No written agreement, license,
+    or  royalty  fee  is required for any of the authorized uses.
+    Modifications to this software may be  copyrighted  by  their
+    author  and  need  not  follow  the licensing terms described
+    here, provided that the new terms are  clearly  indicated  on
+    the first page of each file where they apply.
+
+    IN NO EVENT SHALL THE AUTHOR OR DISTRIBUTORS BE LIABLE TO ANY
+    PARTY  FOR  DIRECT,   INDIRECT,   SPECIAL,   INCIDENTAL,   OR
+    CONSEQUENTIAL   DAMAGES  ARISING  OUT  OF  THE  USE  OF  THIS
+    SOFTWARE, ITS DOCUMENTATION, OR ANY DERIVATIVES THEREOF, EVEN
+    IF  THE  AUTHOR  HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH
+    DAMAGE.
+
+    THE  AUTHOR  AND  DISTRIBUTORS  SPECIFICALLY   DISCLAIM   ANY
+    WARRANTIES,  INCLUDING,  BUT  NOT  LIMITED  TO,  THE  IMPLIED
+    WARRANTIES  OF  MERCHANTABILITY,  FITNESS  FOR  A  PARTICULAR
+    PURPOSE,  AND NON-INFRINGEMENT.  THIS SOFTWARE IS PROVIDED ON
+    AN "AS IS" BASIS, AND THE AUTHOR  AND  DISTRIBUTORS  HAVE  NO
+    OBLIGATION   TO   PROVIDE   MAINTENANCE,   SUPPORT,  UPDATES,
+    ENHANCEMENTS, OR MODIFICATIONS.

src/pl/tcl/mkMakefile.tcldefs

+#!/bin/sh
+if [ -f ./tclConfig.sh ]; then
+    . ./tclConfig.sh
+else
+    if [ -f /usr/lib/tclConfig.sh ]; then
+	echo "using tclConfig.sh from /usr/lib"
+	. /usr/lib/tclConfig.sh
+    else
+	if [ -f /usr/local/lib/tclConfig.sh ]; then
+	    echo "using tclConfig.sh from /usr/local/lib"
+	    . /usr/local/lib/tclConfig.sh
+	else
+	    echo "tclConfig.sh not found in /usr/lib or /usr/local/lib"
+	    echo "I need this file! Please make a symbolic link to this file"
+	    echo "and start make again."
+	    exit 1
+        fi
+    fi
+fi
+
+set | grep '^TCL' >Makefile.tcldefs
+exit 0