fixes in Makefile

In order to be ready to the meson build and be able
to support parallel installcheck do the following:
 - fix use of USE_MODULE_DB
 - isolation target should be included from the gloabl makefile
 - reorder vars to make it easy to read

+ fix out of source check target

tags: pg_query_state

Author: Maxim Orlov

Makefile

@@ -8,10 +8,20 @@ EXTVERSION = 1.1
 DATA = pg_query_state--1.0--1.1.sql
 DATA_built = $(EXTENSION)--$(EXTVERSION).sql
 PGFILEDESC = "pg_query_state - facility to track progress of plan execution"
-EXTRA_REGRESS_OPTS=--temp-config=$(top_srcdir)/$(subdir)/test.conf
+
 EXTRA_CLEAN = ./isolation_output $(EXTENSION)--$(EXTVERSION).sql \
 	Dockerfile ./tests/*.pyc ./tmp_stress
 
+ISOLATION = corner_cases
+#
+# PG11 doesn't support ISOLATION_OPTS variable. We have to use
+# "CREATE/DROP EXTENTION" command in spec.
+#
+# One day, when we'll get rid of PG11, it will be possible to uncomment this
+# variable and remove "CREATE EXTENTION" from spec.
+#
+# ISOLATION_OPTS = --load-extension=pg_query_state
+
 ifdef USE_PGXS
 PG_CONFIG ?= pg_config
 PGXS := $(shell $(PG_CONFIG) --pgxs)
@@ -21,11 +31,17 @@ subdir = contrib/pg_query_state
 top_builddir = ../..
 include $(top_builddir)/src/Makefile.global
 include $(top_srcdir)/contrib/contrib-global.mk
+# need this to provide make check in case of "in source" build
+EXTRA_REGRESS_OPTS=--temp-config=$(top_srcdir)/$(subdir)/test.conf
 endif
 
 $(EXTENSION)--$(EXTVERSION).sql: init.sql
 	cat $^ > $@
 
+#
+# Make conditional targets to save backward compatibility with PG11.
+#
+ifeq ($(MAJORVERSION),11)
 ISOLATIONCHECKS = corner_cases
 
 check: isolationcheck
@@ -46,3 +62,4 @@ submake-isolation:
 	$(MAKE) -C $(top_builddir)/src/test/isolation all
 
 temp-install: EXTRA_INSTALL=contrib/pg_query_state
+endif