diff --git a/TODO b/TODO
index a604db1c6..aa6c8e839 100644
--- a/TODO
+++ b/TODO
@@ -11,7 +11,7 @@ Fix regression test failures:
 ______
 Fix build system:
 
-- ksh does not currently build on AIX or QNX.
+- ksh does not currently build on QNX.
 
 ______
 Fix currently known bugs affecting shell scripting. These are identified by
diff --git a/src/cmd/INIT/iffe.sh b/src/cmd/INIT/iffe.sh
index a802f9497..bfd29ab83 100644
--- a/src/cmd/INIT/iffe.sh
+++ b/src/cmd/INIT/iffe.sh
@@ -26,6 +26,9 @@
 # NOTE: .exe a.out suffix and [\\/] in path patterns for dos/nt
 
 (command set -o posix) 2>/dev/null && set -o posix
+case `uname -s` in
+AIX)	unset LIBPATH ;;
+esac
 
 command=iffe
 version=2012-07-17 # update in USAGE too #
diff --git a/src/cmd/builtin/pty.c b/src/cmd/builtin/pty.c
index 9bfe44a37..72e586dcf 100644
--- a/src/cmd/builtin/pty.c
+++ b/src/cmd/builtin/pty.c
@@ -116,6 +116,10 @@ USAGE_LICENSE
 #define MODE_666	(S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH)
 #define MAXNAME		64
 
+#ifndef CMIN
+#define CMIN		1
+#endif
+
 #if !_lib_openpty && !_lib__getpty && !defined(_pty_clone)
 # if !_lib_grantpt || !_lib_unlock
 #   if !_lib_ptsname
diff --git a/src/cmd/ksh93/README b/src/cmd/ksh93/README
index 279387283..45be42c0c 100644
--- a/src/cmd/ksh93/README
+++ b/src/cmd/ksh93/README
@@ -167,22 +167,24 @@ things amiss), two asterisks signify moderate regression test failures
 (some functionality does not work), and three asterisks signify serious
 failures (crashes, and/or essential functionality does not work).
 
-*	DragonFly BSD on x86_64
-	FreeBSD on x86_64
-	GNU/Linux: CentOS on x86_64
-	GNU/Linux: Debian on x86_64
-	GNU/Linux: Gentoo on i386
-	GNU/Linux: NixOS on x86_64
-	GNU/Linux: Slackware on x86_64
-	GNU/Linux: Ubuntu on x86_64
-***	HP-UX 11 on pa-risc
+*	AIX 7.1 on RISC (PowerPC)
+*	DragonFly BSD 5.8 on x86_64
+	FreeBSD 12.2 on x86_64
+	FreeBSD 12.2 on arm64 (thanks to hyenias for donating access to a Pi)
+	GNU/Linux: CentOS 8.2 on x86_64
+	GNU/Linux: Debian 10.7 on x86_64
+	GNU/Linux: Gentoo 2.7 on i386
+	GNU/Linux: NixOS 19.09 on x86_64
+	GNU/Linux: Slackware 14.2 on x86_64
+	GNU/Linux: Ubuntu 16.04 on x86_64
+***	HP-UX B.11.11 on pa-risc
 *	illumos: OmniOS 2020-08-19 (gcc) on x86_64
 	macOS 10.14.6 (Mojave) on x86_64
-***	NetBSD on x86_64
-**	OpenBSD on x86_64
+***	NetBSD 8.1 and 9.0 on x86_64
+*	OpenBSD 6.8 on x86_64
 *	Solaris 11.4 (gcc) on x86_64
 	Solaris 11.4 (Solaris Studio 12.5 cc) on x86_64
-***	UnixWare 7.1.4 on x86
+*	UnixWare 7.1.4 on x86
 ***	Windows 7 using Cygwin on x86
 
 Good luck!!