Put back libpq link, but make sure that libpq's in-tree directory is

mentioned before the system directories.

src/interfaces/ecpg/test/Makefile.regress

@@ -2,8 +2,8 @@ override CPPFLAGS := -I../../include -I$(top_srcdir)/src/interfaces/ecpg/include
 	-I$(libpq_srcdir) $(CPPFLAGS) 
 override CFLAGS += $(PTHREAD_CFLAGS) 
 
-override LDFLAGS := -L../../ecpglib -L../../pgtypeslib $(LDFLAGS)
-override LIBS := -lecpg -lpgtypes $(LIBS) $(PTHREAD_LIBS)
+override LDFLAGS := -L../../ecpglib -L../../pgtypeslib $(filter-out -l%, $(libpq)) $(LDFLAGS)
+override LIBS := -lecpg -lpgtypes $(filter -l%, $(libpq)) $(LIBS) $(PTHREAD_LIBS)
 
 ECPG = ../../preproc/ecpg --regression -I$(srcdir)/../../include