chore: compile postgres statically to reduce the PLT function call

When building postgres, link all the *.o files directly into the binary
instead of linking libpostgres.so. This approach reduces the overhead of
PLT function calls. Based on our internal performance tests, this change
improves the performance of a 1TB TPC-DS benchmark by 5-8%.

and generate libpostgres.so at the same time, so that other extensions can
write unit tests.

Author: gongxun0928

src/backend/Makefile

@@ -74,7 +74,7 @@ endif
 
 ##########################################################################
 
-all: submake-libpgport submake-catalog-headers submake-utils-headers postgres $(POSTGRES_IMP)
+all: submake-libpgport submake-catalog-headers submake-utils-headers postgres libpostgres.so $(POSTGRES_IMP)
 
 ifneq ($(PORTNAME), cygwin)
 ifneq ($(PORTNAME), win32)
@@ -85,10 +85,8 @@ libpostgres.so: $(OBJS)
 	$(CXX) -shared $(CXXFLAGS) $(LDFLAGS) $(LDFLAGS_SL) $(export_dynamic) \
 	  $(filter-out main/main.o, $(call expand_subsys,$^)) $(LIBS) -o $@
 
-postgres: main/main.o libpostgres.so $(top_builddir)/src/port/libpgport_srv.a $(top_builddir)/src/common/libpgcommon_srv.a
-	$(CXX) $(CXXFLAGS) $(LDFLAGS) $(LDFLAGS_EX) $(export_dynamic) \
-	  main/main.o libpostgres.so $(top_builddir)/src/port/libpgport_srv.a \
-	  $(top_builddir)/src/common/libpgcommon_srv.a $(LIBS) -o $@
+postgres: $(OBJS)
+	$(CXX) $(CXXFLAGS) $(call expand_subsys,$^) $(LDFLAGS) $(LDFLAGS_EX) $(export_dynamic) $(LIBS) -o $@
 
 else
 postgres: $(OBJS)