Index: cygwin/environ.cc
===================================================================
RCS file: /cvs/src/src/winsup/cygwin/environ.cc,v
retrieving revision 1.209
diff -u -p -r1.209 environ.cc
--- cygwin/environ.cc	24 Nov 2013 12:13:33 -0000	1.209
+++ cygwin/environ.cc	24 Dec 2013 15:54:09 -0000
@@ -130,6 +130,7 @@ static struct parse_thing
   {"export", {&export_settings}, setbool, NULL, {{false}, {true}}},
   {"glob", {func: glob_init}, isfunc, NULL, {{0}, {s: "normal"}}},
   {"pipe_byte", {&pipe_byte}, setbool, NULL, {{false}, {true}}},
+  {"pipe_nooverlap", {&pipe_nooverlap}, setbool, NULL, {{false}, {true}}},
   {"proc_retry", {func: set_proc_retry}, isfunc, NULL, {{0}, {5}}},
   {"reset_com", {&reset_com}, setbool, NULL, {{false}, {true}}},
   {"wincmdln", {&wincmdln}, setbool, NULL, {{false}, {true}}},
Index: cygwin/globals.cc
===================================================================
RCS file: /cvs/src/src/winsup/cygwin/globals.cc,v
retrieving revision 1.55
diff -u -p -r1.55 globals.cc
--- cygwin/globals.cc	9 Dec 2013 20:32:24 -0000	1.55
+++ cygwin/globals.cc	24 Dec 2013 15:54:09 -0000
@@ -72,6 +72,7 @@ bool detect_bloda;
 bool dos_file_warning = true;
 bool ignore_case_with_glob;
 bool pipe_byte;
+bool pipe_nooverlap;
 bool reset_com;
 bool wincmdln;
 winsym_t allow_winsymlinks = WSYM_sysfile;
Index: cygwin/pipe.cc
===================================================================
RCS file: /cvs/src/src/winsup/cygwin/pipe.cc,v
retrieving revision 1.148
diff -u -p -r1.148 pipe.cc
--- cygwin/pipe.cc	1 May 2013 01:20:37 -0000	1.148
+++ cygwin/pipe.cc	24 Dec 2013 15:54:09 -0000
@@ -342,7 +342,8 @@ fhandler_pipe::create (fhandler_pipe *fh
   SECURITY_ATTRIBUTES *sa = sec_none_cloexec (mode);
   int res = -1;
 
-  int ret = create (sa, &r, &w, psize, NULL, FILE_FLAG_OVERLAPPED);
+  int ret = create (sa, &r, &w, psize, NULL,
+		   pipe_nooverlap ? 0 : FILE_FLAG_OVERLAPPED);
   if (ret)
     __seterrno_from_win_error (ret);
   else if ((fhs[0] = (fhandler_pipe *) build_fh_dev (*piper_dev)) == NULL)
Index: doc/cygwinenv.xml
===================================================================
RCS file: /cvs/src/src/winsup/doc/cygwinenv.xml,v
retrieving revision 1.4
diff -u -p -r1.4 cygwinenv.xml
--- doc/cygwinenv.xml	26 Jul 2013 17:27:59 -0000	1.4
+++ doc/cygwinenv.xml	24 Dec 2013 15:54:09 -0000
@@ -68,6 +68,11 @@ message mode.</para>
 </listitem>
 
 <listitem>
+<para><envar>(no)pipe_nooverlap</envar> - causes Cygwin to open pipes in non-overlapped mode by default, rather
+than overlapped mode.  Useful for when running a Win32 program that doesn't expect an overlapped pipe.</para>
+</listitem>
+
+<listitem>
 <para><envar>proc_retry:n</envar> - causes <function>fork()</function> and
 <function>exec*()</function> to retry n times when a child process fails
 due to certain windows-specific errors.  These errors usually occur when