diff --git a/contrib/adminpack/Makefile b/contrib/adminpack/Makefile
index 630fea7726..851504f4ae 100644
--- a/contrib/adminpack/Makefile
+++ b/contrib/adminpack/Makefile
@@ -4,7 +4,6 @@ MODULE_big = adminpack
 OBJS = \
 	$(WIN32RES) \
 	adminpack.o
-PG_CPPFLAGS = -I$(libpq_srcdir)
 
 EXTENSION = adminpack
 DATA = adminpack--1.0.sql adminpack--1.0--1.1.sql adminpack--1.1--2.0.sql\
diff --git a/contrib/old_snapshot/Makefile b/contrib/old_snapshot/Makefile
index 77c85df322..adb557532f 100644
--- a/contrib/old_snapshot/Makefile
+++ b/contrib/old_snapshot/Makefile
@@ -4,7 +4,6 @@ MODULE_big = old_snapshot
 OBJS = \
 	$(WIN32RES) \
 	time_mapping.o
-PG_CPPFLAGS = -I$(libpq_srcdir)
 
 EXTENSION = old_snapshot
 DATA = old_snapshot--1.0.sql