diff --git a/src/cmd/ksh93/features/poll b/src/cmd/ksh93/features/poll
index a49dd08ff..21bfadfca 100644
--- a/src/cmd/ksh93/features/poll
+++ b/src/cmd/ksh93/features/poll
@@ -10,6 +10,7 @@ tst	pipe_socketpair note{ use socketpair() for peekable pipe() }end execute{
 	#include <signal.h>
 	#include <sys/types.h>
 	#include <sys/socket.h>
+	#include <sys/wait.h>
 	#ifndef SHUT_RD
 	#define SHUT_RD		0
 	#endif
diff --git a/src/lib/libast/features/fs b/src/lib/libast/features/fs
index b317f006f..54fcd6d92 100644
--- a/src/lib/libast/features/fs
+++ b/src/lib/libast/features/fs
@@ -136,6 +136,16 @@ lib	w_getmntent
 lib	statfs,statvfs
 
 lib	statfs4 sys/types.h - sys/statfs.h - sys/vfs.h - sys/mount.h compile{
+	#include <sys/types.h>
+	#if _sys_statfs
+	#include <sys/statfs.h>
+	#endif
+	#if _sys_vfs
+	#include <sys/vfs.h>
+	#endif
+	#if _sys_mount
+	#include <sys/mount.h>
+	#endif
 	int f()
 	{
 		struct statfs fs;
diff --git a/src/lib/libast/features/lib b/src/lib/libast/features/lib
index b0d7c4ad7..75003dc36 100644
--- a/src/lib/libast/features/lib
+++ b/src/lib/libast/features/lib
@@ -5,8 +5,12 @@ cmd	universe
 hdr	dirent,direntry,filio,fmtmsg,fnmatch,jioctl,libgen,limits
 hdr	locale,ndir,nl_types,process,spawn,syslog,utime,vfork
 hdr	linux/fs,linux/msdos_fs,sys/ioctl
+hdr	wctype
 hdr	wchar note{ <wchar.h> and isw*() really work }end execute{
 	#include <wchar.h>
+	#if _hdr_wctype
+	#include <wctype.h>
+	#endif
 	int
 	main()
 	{
@@ -14,7 +18,6 @@ hdr	wchar note{ <wchar.h> and isw*() really work }end execute{
 		return iswalnum(w) == 0;
 	}
 }end
-hdr	wctype wchar.h
 
 dat	_tzname,tzname
 
@@ -192,6 +195,7 @@ tst	pipe_rw note{ full duplex pipes }end execute{
 
 tst	lib_vfork unistd.h stdlib.h vfork.h note{ vfork exists and it works }end execute{
 	#include <signal.h>
+	#include <sys/wait.h>
 	int
 	main(argc, argv)
 	int	argc;
diff --git a/src/lib/libast/features/mmap b/src/lib/libast/features/mmap
index 21a391c3e..934a6d333 100644
--- a/src/lib/libast/features/mmap
+++ b/src/lib/libast/features/mmap
@@ -122,6 +122,8 @@ tst	lib_mmap64 note{ mmap64 interface and implementation work }end execute{
 	#include <sys/types.h>
 	#include <sys/mman.h>
 	#include <sys/stat.h>
+	#include <stdlib.h>
+	#include <string.h>
 	
 	int
 	main()
diff --git a/src/lib/libast/features/sfio b/src/lib/libast/features/sfio
index e3d251368..d0f6f6807 100644
--- a/src/lib/libast/features/sfio
+++ b/src/lib/libast/features/sfio
@@ -128,6 +128,8 @@ tst	lib_cvt note{ native floating point conversions ok }end link{
 }end
 
 tst	xopen_stdio note{ Stdio fseek/fflush are X/Open-compliant }end execute{
+	#include <fcntl.h>
+	#include <unistd.h>
 	#define Failed(file)	(unlink(file),1)
 	int
 	main(argc, argv)
diff --git a/src/lib/libast/features/syscall b/src/lib/libast/features/syscall
index 9788b9b5b..97c795b89 100644
--- a/src/lib/libast/features/syscall
+++ b/src/lib/libast/features/syscall
@@ -1,5 +1,6 @@
 lib	sysgetcwd note{ syscall(SYS_getcwd,buf,len) implemented }end link{
 	#include <sys/syscall.h>
+	#include <unistd.h>
 	int main()
 	{
 		char	buf[256];
diff --git a/src/lib/libast/features/vmalloc b/src/lib/libast/features/vmalloc
index 1228cb831..dd5d44e45 100644
--- a/src/lib/libast/features/vmalloc
+++ b/src/lib/libast/features/vmalloc
@@ -78,7 +78,8 @@ tst	map_malloc note{ map malloc to _ast_malloc -- wimp-o mach? }end noexecute{
 	#if _map_malloc
 	int main() { return 0; }
 	#else
-	void* calloc(unsigned n, unsigned m) { exit(1); }
+	#include <stdlib.h>
+	void* calloc(size_t n, size_t m) { exit(1); }
 	int main() { return 0; }
 	#endif
 }end
@@ -100,7 +101,8 @@ tst	mal_alloca note{ alloca is based on malloc() }end execute{
 	#if _hdr_alloca
 	#include	<alloca.h>
 	#endif
-	void* malloc(unsigned int size)
+	#include <stdlib.h>
+	void* malloc(size_t size)
 	{	exit(0);
 		return 0;
 	}