diff -ru bdwgc.orig/os_dep.c bdwgc/os_dep.c
--- bdwgc.orig/os_dep.c	2017-01-13 01:05:27.201020300 +0100
+++ bdwgc/os_dep.c	2017-01-12 22:54:52.681020300 +0100
@@ -32,7 +32,7 @@
 #endif
 
 #if defined(UNIX_LIKE) || defined(CYGWIN32) || defined(NACL) \
-    || defined(SYMBIAN)
+    || defined(SYMBIAN) || defined(MIDIPIX)
 # include <fcntl.h>
 #endif

--- bdwgc/include/private/gcconfig.h.orig	2018-11-14 15:26:02.756000000 +0000
+++ bdwgc/include/private/gcconfig.h	2018-11-14 16:42:13.244000000 +0000
@@ -108,6 +108,10 @@
 #   define LINUX
 # endif
 
+# if defined(__midipix__)
+#    define MIDIPIX
+# endif
+
 /* And one for QNX: */
 # if defined(__QNX__)
 #    define I386
@@ -362,6 +366,14 @@
 #    define X86_64
 #    define mach_type_known
 # endif
+# if defined(MIDIPIX) && defined(__x86_64__)
+#    define X86_64
+#    define mach_type_known
+# endif
+# if defined(MIDIPIX) && defined(__i386__)
+#    define I386
+#    define mach_type_known
+# endif
 # if defined(LINUX) && (defined(__ia64__) || defined(__ia64))
 #    define IA64
 #    define mach_type_known
@@ -1542,6 +1554,12 @@
           EXTERN_C_BEGIN
 #       endif
 #   endif
+#   ifdef MIDIPIX
+#      define OS_TYPE "MIDIPIX"
+#	define DATASTART (ptr_t)NULL /* Wrong */
+#	define DATAEND (ptr_t)NULL /* Wrong */
+#	define STACKBOTTOM (ptr_t)0x000000 /* Not sure if we should be using STACKBOTTOM or LINUX_STACKBOTTOM & /proc/self/stat */
+#   endif
 #   ifdef CYGWIN32
 #       define OS_TYPE "CYGWIN32"
 #       define DATASTART ((ptr_t)GC_DATASTART)  /* From gc.h */
@@ -2656,6 +2674,12 @@
           EXTERN_C_BEGIN
 #       endif
 #   endif
+#   ifdef MIDIPIX
+#      define OS_TYPE "MIDIPIX"
+#	define DATASTART (ptr_t)NULL /* Wrong */
+#	define DATAEND (ptr_t)NULL /* Wrong */
+#	define STACKBOTTOM (ptr_t)0x000000 /* Not sure if we should be using STACKBOTTOM or LINUX_STACKBOTTOM & /proc/self/stat */
+#   endif
 #   ifdef DARWIN
 #     define OS_TYPE "DARWIN"
 #     define DARWIN_DONT_PARSE_STACK
@@ -3242,7 +3266,7 @@
 # if defined(GC_IRIX_THREADS) && !defined(IRIX5)
 #   error Inconsistent configuration
 # endif
-# if defined(GC_LINUX_THREADS) && !defined(LINUX) && !defined(NACL)
+# if defined(GC_LINUX_THREADS) && !defined(LINUX) && !defined(NACL) && !defined(MIDIPIX)
 #   error Inconsistent configuration
 # endif
 # if defined(GC_NETBSD_THREADS) && !defined(NETBSD)
--- bdwgc/pthread_stop_world.c.orig	2017-01-23 18:47:24.683963226 +0000
+++ bdwgc/pthread_stop_world.c	2017-01-23 18:59:56.449597256 +0000
@@ -20,6 +20,10 @@
 #if defined(GC_PTHREADS) && !defined(GC_WIN32_THREADS) && \
     !defined(GC_DARWIN_THREADS)
 
+#ifdef MIDIPIX
+# include <sys/select.h>
+#endif
+
 #ifdef NACL
 
 # include <unistd.h>