Our test to see if we had permission to install into Perl5 install area

always failed if Perl makefile's INSTALLSITELIB variable was specified
in terms of another variable.  Fix by adding an echo-installdir target
to the Perl makefile, which the upper-level Makefile can invoke.

src/interfaces/Makefile

@@ -7,7 +7,7 @@
 #
 #
 # IDENTIFICATION
-#    $Header: /cvsroot/pgsql/src/interfaces/Makefile,v 1.35 2000/04/20 17:21:46 momjian Exp $
+#    $Header: /cvsroot/pgsql/src/interfaces/Makefile,v 1.36 2000/04/23 04:26:31 tgl Exp $
 #
 #-------------------------------------------------------------------------
 
@@ -53,7 +53,7 @@ install-perl5: perl5/Makefile
 	$(MAKE) -C perl5 clean
 	cd perl5 && POSTGRES_HOME="$(POSTGRESDIR)" $(PERL) Makefile.PL POLLUTE=1
 	$(MAKE) -C perl5 all
-	-@if [ -w `sed -n -e 's/^ *INSTALLSITELIB *= *//p' perl5/Makefile` ]; then \
+	-@if [ -w `$(MAKE) --quiet -C perl5 echo-installdir` ]; then \
 		$(MAKE) $(MFLAGS) -C perl5 install; \
 		rm -f perl5/Makefile; \
 	else \

src/interfaces/perl5/Makefile.PL

@@ -1,6 +1,6 @@
 #-------------------------------------------------------
 #
-# $Id: Makefile.PL,v 1.14 1998/10/18 02:36:48 tgl Exp $
+# $Id: Makefile.PL,v 1.15 2000/04/23 04:26:32 tgl Exp $
 #
 # Copyright (c) 1997, 1998  Edmund Mergl
 #
@@ -53,6 +53,14 @@ where Postgres is installed (often /usr/local/pgsql).\n";
 
 WriteMakefile(%opts);
 
-exit(0);
 
-# end of Makefile.PL
+sub MY::installbin { 
+
+q[
+# Create a target that interfaces/Makefile can use to
+# determine the Perl install directory.
+echo-installdir:
+	@echo $(INSTALLSITELIB)
+];
+
+}