diff --git a/Build.sh b/Build.sh
index 7161fc2..bd1496f 100644
--- a/Build.sh
+++ b/Build.sh
@@ -1,5 +1,5 @@
 #!/bin/sh
-srcversion='$MirOS: src/bin/mksh/Build.sh,v 1.687 2015/07/09 20:11:44 tg Exp $'
+srcversion='$MirOS: src/bin/mksh/Build.sh,v 1.688 2015/07/09 20:52:34 tg Exp $'
 #-
 # Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
 #		2011, 2012, 2013, 2014, 2015
@@ -1673,6 +1673,7 @@ ac_header sys/select.h sys/types.h
 ac_header sys/sysmacros.h
 ac_header bstring.h
 ac_header grp.h sys/types.h
+ac_header io.h
 ac_header libgen.h
 ac_header libutil.h sys/types.h
 ac_header paths.h
@@ -2340,7 +2341,7 @@ addsrcs '!' HAVE_STRLCPY strlcpy.c
 addsrcs USE_PRINTF_BUILTIN printf.c
 test 1 = "$USE_PRINTF_BUILTIN" && add_cppflags -DMKSH_PRINTF_BUILTIN
 test 1 = "$HAVE_CAN_VERB" && CFLAGS="$CFLAGS -verbose"
-add_cppflags -DMKSH_BUILD_R=510
+add_cppflags -DMKSH_BUILD_R=511
 
 $e $bi$me: Finished configuration testing, now producing output.$ao
 
diff --git a/Makefile b/Makefile
index 2485e08..db6e767 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-# $MirOS: src/bin/mksh/Makefile,v 1.141 2015/04/11 23:28:17 tg Exp $
+# $MirOS: src/bin/mksh/Makefile,v 1.142 2015/07/09 20:52:36 tg Exp $
 #-
 # Copyright (c) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
 #		2011, 2012, 2013, 2014, 2015
@@ -43,21 +43,22 @@ CPPFLAGS+=	-DMKSH_ASSUME_UTF8 -DMKSH_DISABLE_DEPRECATED \
 		-DHAVE_SYS_MKDEV_H=0 -DHAVE_SYS_MMAN_H=1 -DHAVE_SYS_PARAM_H=1 \
 		-DHAVE_SYS_RESOURCE_H=1 -DHAVE_SYS_SELECT_H=1 \
 		-DHAVE_SYS_SYSMACROS_H=0 -DHAVE_BSTRING_H=0 -DHAVE_GRP_H=1 \
-		-DHAVE_LIBGEN_H=1 -DHAVE_LIBUTIL_H=0 -DHAVE_PATHS_H=1 \
-		-DHAVE_STDINT_H=1 -DHAVE_STRINGS_H=1 -DHAVE_TERMIOS_H=1 \
-		-DHAVE_ULIMIT_H=0 -DHAVE_VALUES_H=0 -DHAVE_CAN_INTTYPES=1 \
-		-DHAVE_CAN_UCBINTS=1 -DHAVE_CAN_INT8TYPE=1 \
-		-DHAVE_CAN_UCBINT8=1 -DHAVE_RLIM_T=1 -DHAVE_SIG_T=1 \
-		-DHAVE_SYS_ERRLIST=1 -DHAVE_SYS_SIGNAME=1 -DHAVE_SYS_SIGLIST=1 \
-		-DHAVE_FLOCK=1 -DHAVE_LOCK_FCNTL=1 -DHAVE_GETRUSAGE=1 \
-		-DHAVE_GETSID=1 -DHAVE_GETTIMEOFDAY=1 -DHAVE_ISSETUGID=1 \
-		-DHAVE_KILLPG=1 -DHAVE_MEMMOVE=1 -DHAVE_MKNOD=0 -DHAVE_MMAP=1 \
-		-DHAVE_NICE=1 -DHAVE_REVOKE=1 -DHAVE_SETLOCALE_CTYPE=0 \
-		-DHAVE_LANGINFO_CODESET=0 -DHAVE_SELECT=1 -DHAVE_SETRESUGID=1 \
-		-DHAVE_SETGROUPS=1 -DHAVE_STRERROR=0 -DHAVE_STRSIGNAL=0 \
-		-DHAVE_STRLCPY=1 -DHAVE_FLOCK_DECL=1 -DHAVE_REVOKE_DECL=1 \
+		-DHAVE_IO_H=0 -DHAVE_LIBGEN_H=1 -DHAVE_LIBUTIL_H=0 \
+		-DHAVE_PATHS_H=1 -DHAVE_STDINT_H=1 -DHAVE_STRINGS_H=1 \
+		-DHAVE_TERMIOS_H=1 -DHAVE_ULIMIT_H=0 -DHAVE_VALUES_H=0 \
+		-DHAVE_CAN_INTTYPES=1 -DHAVE_CAN_UCBINTS=1 \
+		-DHAVE_CAN_INT8TYPE=1 -DHAVE_CAN_UCBINT8=1 -DHAVE_RLIM_T=1 \
+		-DHAVE_SIG_T=1 -DHAVE_SYS_ERRLIST=1 -DHAVE_SYS_SIGNAME=1 \
+		-DHAVE_SYS_SIGLIST=1 -DHAVE_FLOCK=1 -DHAVE_LOCK_FCNTL=1 \
+		-DHAVE_GETRUSAGE=1 -DHAVE_GETSID=1 -DHAVE_GETTIMEOFDAY=1 \
+		-DHAVE_ISSETUGID=1 -DHAVE_KILLPG=1 -DHAVE_MEMMOVE=1 \
+		-DHAVE_MKNOD=0 -DHAVE_MMAP=1 -DHAVE_NICE=1 -DHAVE_REVOKE=1 \
+		-DHAVE_SETLOCALE_CTYPE=0 -DHAVE_LANGINFO_CODESET=0 \
+		-DHAVE_SELECT=1 -DHAVE_SETRESUGID=1 -DHAVE_SETGROUPS=1 \
+		-DHAVE_STRERROR=0 -DHAVE_STRSIGNAL=0 -DHAVE_STRLCPY=1 \
+		-DHAVE_FLOCK_DECL=1 -DHAVE_REVOKE_DECL=1 \
 		-DHAVE_SYS_ERRLIST_DECL=1 -DHAVE_SYS_SIGLIST_DECL=1 \
-		-DHAVE_PERSISTENT_HISTORY=1 -DMKSH_BUILD_R=510
+		-DHAVE_PERSISTENT_HISTORY=1 -DMKSH_BUILD_R=511
 CPPFLAGS+=	-D${${PROG:L}_tf:C/(Mir${MAN:E}{0,1}){2}/4/:S/x/mksh_BUILD/:U}
 CPPFLAGS+=	-I.
 COPTS+=		-std=c89 -Wall
diff --git a/check.t b/check.t
index 820c136..7ee8d44 100644
--- a/check.t
+++ b/check.t
@@ -1,4 +1,4 @@
-# $MirOS: src/bin/mksh/check.t,v 1.701 2015/07/09 20:11:45 tg Exp $
+# $MirOS: src/bin/mksh/check.t,v 1.702 2015/07/09 20:52:36 tg Exp $
 # -*- mode: sh -*-
 #-
 # Copyright © 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010,
@@ -30,7 +30,7 @@
 # (2013/12/02 20:39:44) http://openbsd.cs.toronto.edu/cgi-bin/cvsweb/src/regress/bin/ksh/?sortby=date
 
 expected-stdout:
-	@(#)MIRBSD KSH R51 2015/07/06
+	@(#)MIRBSD KSH R51 2015/07/09
 description:
 	Check version of shell.
 stdin:
@@ -39,7 +39,7 @@ name: KSH_VERSION
 category: shell:legacy-no
 ---
 expected-stdout:
-	@(#)LEGACY KSH R51 2015/07/06
+	@(#)LEGACY KSH R51 2015/07/09
 description:
 	Check version of legacy shell.
 stdin:
@@ -8613,6 +8613,7 @@ stdin:
 	cat >foo <<-'EOF'
 		x='bar
 		' #
+		echo .${#x} #
 		if test x"$KSH_VERSION" = x""; then #
 			printf '<%s>' "$x" #
 		else #
@@ -8624,8 +8625,10 @@ stdin:
 		print -r -- "{$line}"
 	done
 expected-stdout:
-	[<bar
+	[.5
+	<bar
 	>]
+	{.5}
 	{<bar
}
 ---
 name: print-lf
@@ -8635,6 +8638,7 @@ stdin:
 	cat >foo <<-'EOF'
 		x='bar
 		' #
+		echo .${#x} #
 		if test x"$KSH_VERSION" = x""; then #
 			printf '<%s>' "$x" #
 		else #
@@ -8646,8 +8650,10 @@ stdin:
 		print -r -- "{$line}"
 	done
 expected-stdout:
-	[<bar
+	[.4
+	<bar
 	>]
+	{.4}
 	{<bar}
 ---
 name: print-nul-chars
diff --git a/exec.c b/exec.c
index 481b34f..2e98528 100644
--- a/exec.c
+++ b/exec.c
@@ -23,7 +23,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/exec.c,v 1.158 2015/07/09 20:20:42 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/exec.c,v 1.159 2015/07/09 20:52:38 tg Exp $");
 
 #ifndef MKSH_DEFAULT_EXECSHELL
 #define MKSH_DEFAULT_EXECSHELL	"/bin/sh"
@@ -925,7 +925,7 @@ scriptexec(struct op *tp, const char **ap)
 	*tp->args-- = tp->str;
 
 #ifndef MKSH_SMALL
-	if ((fd = open(tp->str, O_RDONLY | O_BINARY)) >= 0) {
+	if ((fd = binopen2(tp->str, O_RDONLY)) >= 0) {
 		unsigned char *cp;
 		unsigned short m;
 		ssize_t n;
@@ -1445,7 +1445,7 @@ iosetup(struct ioword *iop, struct tbl *tp)
 			warningf(true, "%s: %s", cp, "restricted");
 			return (-1);
 		}
-		u = open(cp, flags | O_BINARY, 0666);
+		u = binopen3(cp, flags, 0666);
 	}
 	if (u < 0) {
 		/* herein() may already have printed message */
@@ -1578,7 +1578,7 @@ herein(struct ioword *iop, char **resbuf)
 	 * so temp doesn't get removed too soon).
 	 */
 	h = maketemp(ATEMP, TT_HEREDOC_EXP, &e->temps);
-	if (!(shf = h->shf) || (fd = open(h->tffn, O_RDONLY | O_BINARY, 0)) < 0) {
+	if (!(shf = h->shf) || (fd = binopen3(h->tffn, O_RDONLY, 0)) < 0) {
 		i = errno;
 		warningf(true, "can't %s temporary file %s: %s",
 		    !shf ? "create" : "open", h->tffn, cstrerror(i));
diff --git a/funcs.c b/funcs.c
index 223ab8a..0d2aec3 100644
--- a/funcs.c
+++ b/funcs.c
@@ -38,7 +38,7 @@
 #endif
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/funcs.c,v 1.279 2015/07/09 20:20:42 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/funcs.c,v 1.280 2015/07/09 20:52:39 tg Exp $");
 
 #if HAVE_KILLPG
 /*
@@ -3668,7 +3668,7 @@ c_cat(const char **wp)
 			fn = *wp++;
 			if (ksh_isdash(fn))
 				fd = STDIN_FILENO;
-			else if ((fd = open(fn, O_RDONLY | O_BINARY)) < 0) {
+			else if ((fd = binopen2(fn, O_RDONLY)) < 0) {
 				eno = errno;
 				bi_errorf("%s: %s", fn, cstrerror(eno));
 				rv = 1;
diff --git a/histrap.c b/histrap.c
index d19dbb6..7a96aa8 100644
--- a/histrap.c
+++ b/histrap.c
@@ -27,7 +27,7 @@
 #include <sys/file.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/histrap.c,v 1.148 2015/07/05 19:53:45 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/histrap.c,v 1.149 2015/07/09 20:52:40 tg Exp $");
 
 Trap sigtraps[ksh_NSIG + 1];
 static struct sigaction Sigact_ign;
@@ -764,8 +764,7 @@ hist_init(Source *s)
 
  retry:
 	/* we have a file and are interactive */
-	if ((fd = open(hname, O_RDWR | O_CREAT | O_APPEND | O_BINARY,
-	    0600)) < 0)
+	if ((fd = binopen3(hname, O_RDWR | O_CREAT | O_APPEND, 0600)) < 0)
 		return;
 
 	histfd = savefd(fd);
@@ -800,8 +799,8 @@ hist_init(Source *s)
 
 			/* create temporary file */
 			nhname = shf_smprintf("%s.%d", hname, (int)procpid);
-			if ((fd = open(nhname, O_RDWR | O_CREAT | O_TRUNC |
-			    O_EXCL | O_BINARY, 0600)) < 0) {
+			if ((fd = binopen3(nhname, O_RDWR | O_CREAT | O_TRUNC |
+			    O_EXCL, 0600)) < 0) {
 				/* just don't truncate then, meh. */
 				goto hist_trunc_dont;
 			}
diff --git a/main.c b/main.c
index 3e4dee0..2799829 100644
--- a/main.c
+++ b/main.c
@@ -34,7 +34,7 @@
 #include <locale.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/main.c,v 1.298 2015/07/09 19:46:42 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/main.c,v 1.299 2015/07/09 20:52:40 tg Exp $");
 
 extern char **environ;
 
@@ -193,6 +193,12 @@ main_init(int argc, const char *argv[], Source **sp, struct block **lp)
 	ssize_t k;
 #endif
 
+#ifdef __OS2__
+	for (i = 0; i < 3; ++i)
+		if (!isatty(i))
+			setmode(i, O_BINARY);
+#endif
+
 	/* do things like getpgrp() et al. */
 	chvt_reinit();
 
@@ -1637,7 +1643,7 @@ maketemp(Area *ap, Temp_type type, struct temp **tlist)
 		} while (len < 6);
 
 		/* check if this one works */
-		if ((i = open(tp->tffn, O_CREAT | O_EXCL | O_RDWR | O_BINARY,
+		if ((i = binopen3(tp->tffn, O_CREAT | O_EXCL | O_RDWR,
 		    0600)) < 0 && errno != EEXIST)
 			goto maketemp_out;
 	} while (i < 0);
diff --git a/misc.c b/misc.c
index 8ad5864..c7cfdbc 100644
--- a/misc.c
+++ b/misc.c
@@ -30,7 +30,7 @@
 #include <grp.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/misc.c,v 1.236 2015/07/05 14:58:33 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/misc.c,v 1.237 2015/07/09 20:52:41 tg Exp $");
 
 #define KSH_CHVT_FLAG
 #ifdef MKSH_SMALL
@@ -2009,9 +2009,9 @@ chvt(const Getopt *go)
 #endif
 	    }
 	}
-	if ((fd = open(dv, O_RDWR | O_BINARY)) < 0) {
+	if ((fd = binopen2(dv, O_RDWR)) < 0) {
 		sleep(1);
-		if ((fd = open(dv, O_RDWR | O_BINARY)) < 0) {
+		if ((fd = binopen2(dv, O_RDWR)) < 0) {
 			errorf("%s: %s %s", "chvt", "can't open", dv);
 		}
 	}
diff --git a/sh.h b/sh.h
index 1e5c386..3c8fa5d 100644
--- a/sh.h
+++ b/sh.h
@@ -64,6 +64,9 @@
 #include <dirent.h>
 #include <errno.h>
 #include <fcntl.h>
+#if HAVE_IO_H
+#include <io.h>
+#endif
 #if HAVE_LIBGEN_H
 #include <libgen.h>
 #endif
@@ -169,9 +172,9 @@
 #endif
 
 #ifdef EXTERN
-__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.737 2015/07/09 20:20:45 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.738 2015/07/09 20:52:42 tg Exp $");
 #endif
-#define MKSH_VERSION "R51 2015/07/06"
+#define MKSH_VERSION "R51 2015/07/09"
 
 /* arithmetic types: C implementation */
 #if !HAVE_CAN_INTTYPES
@@ -560,7 +563,7 @@ char *ucstrstr(char *, const char *);
 #define mkssert(e)	do { } while (/* CONSTCOND */ 0)
 #endif
 
-#if (!defined(MKSH_BUILDMAKEFILE4BSD) && !defined(MKSH_BUILDSH)) || (MKSH_BUILD_R != 510)
+#if (!defined(MKSH_BUILDMAKEFILE4BSD) && !defined(MKSH_BUILDSH)) || (MKSH_BUILD_R != 511)
 #error Must run Build.sh to compile this.
 extern void thiswillneverbedefinedIhope(void);
 int
@@ -2081,6 +2084,27 @@ EXTERN bool tty_hasstate;	/* true if tty_state is valid */
 
 extern int tty_init_fd(void);	/* initialise tty_fd, tty_devtty */
 
+#ifdef __OS2__
+#ifndef __GNUC__
+# error oops?
+#endif
+#define binopen2(path,flags)		__extension__({			\
+	int binopen2_fd = open((path), (flags) | O_BINARY);		\
+	if (binopen2_fd >= 0)						\
+		setmode(binopen2_fd, O_BINARY);				\
+	(binopen2_fd);							\
+})
+#define binopen3(path,flags,mode)	__extension__({			\
+	int binopen3_fd = open((path), (flags) | O_BINARY, (mode));	\
+	if (binopen3_fd >= 0)						\
+		setmode(binopen3_fd, O_BINARY);				\
+	(binopen3_fd);							\
+})
+#else
+#define binopen2(path,flags)		open((path), (flags) | O_BINARY)
+#define binopen3(path,flags,mode)	open((path), (flags) | O_BINARY, (mode))
+#endif
+
 /* be sure not to interfere with anyone else's idea about EXTERN */
 #ifdef EXTERN_DEFINED
 # undef EXTERN_DEFINED
diff --git a/shf.c b/shf.c
index 9647ce6..1c9e3d5 100644
--- a/shf.c
+++ b/shf.c
@@ -25,7 +25,7 @@
 
 #include "sh.h"
 
-__RCSID("$MirOS: src/bin/mksh/shf.c,v 1.65 2015/04/29 20:07:35 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/shf.c,v 1.66 2015/07/09 20:52:43 tg Exp $");
 
 /* flags to shf_emptybuf() */
 #define EB_READSW	0x01	/* about to switch to reading */
@@ -62,7 +62,7 @@ shf_open(const char *name, int oflags, int mode, int sflags)
 	shf->flags = SHF_ALLOCS;
 	/* Rest filled in by reopen. */
 
-	fd = open(name, oflags | O_BINARY, mode);
+	fd = binopen3(name, oflags, mode);
 	if (fd < 0) {
 		eno = errno;
 		afree(shf, shf->areap);