Issue 5619: Pass MS CRT debug flags into subprocesses
diff --git a/Misc/ACKS b/Misc/ACKS
index 401b29e..d5b055c 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -685,6 +685,7 @@
 Nathan Sullivan
 Mark Summerfield
 Hisao Suzuki
+Andrew Svetlov
 Kalle Svensson
 Paul Swartz
 Thenault Sylvain
diff --git a/Misc/NEWS b/Misc/NEWS
index 6bded6b..aa99ac0 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -199,6 +199,9 @@
 Library
 -------
 
+- Issue #5619: Multiprocessing children disobey the debug flag and causes
+  popups on windows buildbots. Patch applied to work around this issue.
+
 - Issue #5632: Thread.ident was None for the main thread and threads not created
   with the threading module.
 
diff --git a/Modules/_multiprocessing/win32_functions.c b/Modules/_multiprocessing/win32_functions.c
index 513fc02..549c151 100644
--- a/Modules/_multiprocessing/win32_functions.c
+++ b/Modules/_multiprocessing/win32_functions.c
@@ -130,6 +130,12 @@
 	if (!PyArg_ParseTuple(args, "I", &uExitCode))
 		return NULL;
 
+	#if defined(Py_DEBUG)
+		SetErrorMode(SEM_FAILCRITICALERRORS|SEM_NOALIGNMENTFAULTEXCEPT|SEM_NOGPFAULTERRORBOX|SEM_NOOPENFILEERRORBOX);
+		_CrtSetReportMode(_CRT_ASSERT, _CRTDBG_MODE_DEBUG);
+	#endif
+
+
 	ExitProcess(uExitCode);
 
 	return NULL;
diff --git a/Python/pythonrun.c b/Python/pythonrun.c
index d0c5b2b..b3866ce 100644
--- a/Python/pythonrun.c
+++ b/Python/pythonrun.c
@@ -1634,6 +1634,8 @@
 Py_FatalError(const char *msg)
 {
 	fprintf(stderr, "Fatal Python error: %s\n", msg);
+	fflush(stderr); /* it helps in Windows debug build */
+
 #ifdef MS_WINDOWS
 	{
 		size_t len = strlen(msg);