simplify

Makefile

@@ -34,9 +34,24 @@ postgres.c:
 	sed -i 's/EndCommand/EndCommandMy/' $@
 	sed -i 's/NullCommand/NullCommandMy/' $@
 
-EXTRA_CLEAN = postgres.c
 MODULE_big = pg_task
+
+PG9495 = $(shell $(PG_CONFIG) --version | egrep " 9\.4| 9\.5" > /dev/null && echo yes || echo no)
+ifeq ($(PG9495),yes)
+work.o: latch.h
+latch.h:
+	wget -O $@ "https://raw.githubusercontent.com/postgres/postgres/REL9_6_STABLE/src/include/storage/latch.h"
+latch.c: latch.h
+	wget -O $@ "https://raw.githubusercontent.com/postgres/postgres/REL9_6_STABLE/src/backend/storage/ipc/latch.c"
+	sed -i 's/storage\/latch/latch/' $@
 OBJS = init.o conf.o work.o task.o spi.o dest.o latch.o
+EXTRA_CLEAN = postgres.c latch.c latch.h
+PG_CFLAGS += -Wno-cpp
+else
+OBJS = init.o conf.o work.o task.o spi.o dest.o
+EXTRA_CLEAN = postgres.c
+endif
+
 PG94 = $(shell $(PG_CONFIG) --version | egrep " 8\.| 9\.0| 9\.1| 9\.2| 9\.3" > /dev/null && echo no || echo yes)
 ifeq ($(PG94),no)
 	$(error Minimum version of PostgreSQL required is 9.4.0)