diff --git a/src/cmd/builtin/features/pty b/src/cmd/builtin/features/pty
index df07bcb3d..31cfbbdc0 100755
--- a/src/cmd/builtin/features/pty
+++ b/src/cmd/builtin/features/pty
@@ -13,7 +13,6 @@ lib	openpty,_getpty,ptsname -lutil
 lib	grantpt,unlockpt,posix_openpt stdlib.h
 
 tst - output{
-	#include	<stdio.h>
 	#include	<sys/types.h>
 	#include	<sys/stat.h>
 	#if _lib_ptsname && _npt_ptsname
diff --git a/src/lib/libast/features/float b/src/lib/libast/features/float
index 781f76e0f..0f357eec9 100644
--- a/src/lib/libast/features/float
+++ b/src/lib/libast/features/float
@@ -245,7 +245,6 @@ macro{
 
 tst	- note{ missing floating point limits }end output{
 	#include "FEATURE/common"
-	#include <stdio.h>
 	#if _hdr_float
 	#include <float.h>
 	#endif
@@ -900,7 +899,6 @@ tst	- note{ missing floating point limits }end output{
 
 tst	- note{ double exponent bitfoolery }end output{
 	#include "FEATURE/common"
-	#include <stdio.h>
 	typedef union _dbl_exp_u
 	{
 		unsigned _ast_int4_t	e[sizeof(double) / 4];
@@ -936,7 +934,6 @@ tst	- note{ double exponent bitfoolery }end output{
 
 tst	- note{ long double exponent bitfoolery }end output{
 	#include "FEATURE/common"
-	#include <stdio.h>
 	typedef union _ast_fltmax_exp_u
 	{
 		unsigned _ast_int4_t	e[sizeof(_ast_fltmax_t) / 4];
@@ -971,7 +968,6 @@ tst	- note{ long double exponent bitfoolery }end output{
 }end
 
 tst	- -DN=1 - -DN=2 note{ _ast_fltmax_t maximum integral type }end output{
-	#include <stdio.h>
 	int
 	main()
 	{
@@ -996,7 +992,6 @@ tst	- -DSCAN=1 - -lm -DSTRTO=1 - -DMAC=1 - -DDIV=1 - -DEXP=1 - -DADD=1 - -DMPY=1
 	#define _FP_MODE_VARIABLE	1
 	#endif
 	#include "FEATURE/common"
-	#include <stdio.h>
 	#include <sys/types.h>
 	#include <signal.h>
 	#include <string.h>
diff --git a/src/lib/libast/features/sfio b/src/lib/libast/features/sfio
index 2d240545f..3ec8d1de9 100644
--- a/src/lib/libast/features/sfio
+++ b/src/lib/libast/features/sfio
@@ -7,7 +7,6 @@ key	signed
 typ	struct.sf_hdtr sys/socket.h
 
 tst	- note{ number of bits in pointer }end output{
-	#include <stdio.h>
 	int
 	main()
 	{
diff --git a/src/lib/libast/features/stdio b/src/lib/libast/features/stdio
index 508879f3b..0e5c3b79d 100644
--- a/src/lib/libast/features/stdio
+++ b/src/lib/libast/features/stdio
@@ -204,7 +204,6 @@ cat{
 	#endif
 }end
 output{
-	#include <stdio.h>
 	#ifndef FILENAME_MAX
 	#ifndef NAME_MAX
 	#ifndef _POSIX_NAME_MAX