Fix out-of-tree build for transform modules.

Neither plperl nor plpython installed sufficient header files to
permit transform modules to be built out-of-tree using PGXS. Fix that
by installing all plperl and plpython header files (other than those
with special purposes such as generated data tables), and also install
plpython's special .mk file for mangling regression tests.

(This commit does not fix the windows install, which does not
currently install _any_ plperl or plpython headers.)

Also fix the existing transform modules for hstore and ltree so that
their cross-module #include directives work as anticipated by commit
df163230b9 et seq. This allows them to serve as working examples of
how to reference other modules when doing separate out-of-tree builds.

Discussion: https://postgr.es/m/87o9ej8bgl.fsf%40news-spur.riddles.org.uk

src/pl/plperl/GNUmakefile

@@ -100,7 +100,7 @@ uninstall: uninstall-lib uninstall-data
 
 install-data: installdirs
 	$(INSTALL_DATA) $(addprefix $(srcdir)/, $(DATA)) '$(DESTDIR)$(datadir)/extension/'
-	$(INSTALL_DATA) $(srcdir)/plperl.h $(srcdir)/ppport.h '$(DESTDIR)$(includedir_server)'
+	$(INSTALL_DATA) $(srcdir)/plperl.h $(srcdir)/ppport.h $(srcdir)/plperl_helpers.h '$(DESTDIR)$(includedir_server)'
 
 uninstall-data:
 	rm -f $(addprefix '$(DESTDIR)$(datadir)/extension'/, $(notdir $(DATA)))

src/pl/plpython/Makefile

@@ -39,6 +39,21 @@ ifeq ($(python_majorversion),2)
 DATA += plpythonu.control plpythonu--1.0.sql plpythonu--unpackaged--1.0.sql
 endif
 
+# header files to install - it's not clear which of these might be needed
+# so install them all.
+INCS = 	plpython.h \
+	plpy_cursorobject.h \
+	plpy_elog.h \
+	plpy_exec.h \
+	plpy_main.h \
+	plpy_planobject.h \
+	plpy_plpymodule.h \
+	plpy_procedure.h \
+	plpy_resultobject.h \
+	plpy_spi.h \
+	plpy_subxactobject.h \
+	plpy_typeio.h \
+	plpy_util.h
 
 # Python on win32 ships with import libraries only for Microsoft Visual C++,
 # which are not compatible with mingw gcc. Therefore we need to build a
@@ -105,13 +120,14 @@ $(OBJS): | submake-generated-headers
 install: all install-lib install-data
 
 installdirs: installdirs-lib
-	$(MKDIR_P) '$(DESTDIR)$(datadir)/extension' '$(DESTDIR)$(includedir_server)'
+	$(MKDIR_P) '$(DESTDIR)$(datadir)/extension' '$(DESTDIR)$(includedir_server)' '$(DESTDIR)$(pgxsdir)/src/pl/plpython'
 
 uninstall: uninstall-lib uninstall-data
 
 install-data: installdirs
 	$(INSTALL_DATA) $(addprefix $(srcdir)/, $(DATA)) '$(DESTDIR)$(datadir)/extension/'
-	$(INSTALL_DATA) $(srcdir)/plpython.h $(srcdir)/plpy_util.h '$(DESTDIR)$(includedir_server)'
+	$(INSTALL_DATA) $(addprefix $(srcdir)/, $(INCS)) '$(DESTDIR)$(includedir_server)'
+	$(INSTALL_DATA) $(srcdir)/regress-python3-mangle.mk '$(DESTDIR)$(pgxsdir)/src/pl/plpython'
 
 uninstall-data:
 	rm -f $(addprefix '$(DESTDIR)$(datadir)/extension'/, $(notdir $(DATA)))

src/tools/msvc/Mkvcbuild.pm

@@ -508,7 +508,7 @@ sub mkvcbuild
 		my $hstore_plpython = AddTransformModule(
 			'hstore_plpython' . $pymajorver, 'contrib/hstore_plpython',
 			'plpython' . $pymajorver,        'src/pl/plpython',
-			'hstore',                        'contrib/hstore');
+			'hstore',                        'contrib');
 		$hstore_plpython->AddDefine(
 			'PLPYTHON_LIBNAME="plpython' . $pymajorver . '"');
 		my $jsonb_plpython = AddTransformModule(
@@ -519,7 +519,7 @@ sub mkvcbuild
 		my $ltree_plpython = AddTransformModule(
 			'ltree_plpython' . $pymajorver, 'contrib/ltree_plpython',
 			'plpython' . $pymajorver,       'src/pl/plpython',
-			'ltree',                        'contrib/ltree');
+			'ltree',                        'contrib');
 		$ltree_plpython->AddDefine(
 			'PLPYTHON_LIBNAME="plpython' . $pymajorver . '"');
 	}
@@ -755,7 +755,7 @@ sub mkvcbuild
 		my $hstore_plperl = AddTransformModule(
 			'hstore_plperl', 'contrib/hstore_plperl',
 			'plperl',        'src/pl/plperl',
-			'hstore',        'contrib/hstore');
+			'hstore',        'contrib');
 		my $jsonb_plperl = AddTransformModule(
 			'jsonb_plperl', 'contrib/jsonb_plperl',
 			'plperl',       'src/pl/plperl');