--- bdwgc/configure.ac.orig	2017-05-29 14:42:22.121575637 +0000
+++ bdwgc/configure.ac	2017-05-29 14:48:31.518727090 +0000
@@ -195,6 +195,10 @@
      *-*-hpux10*)
         AC_MSG_WARN("Only HP-UX 11 POSIX threads are supported.")
         ;;
+     *-*-midipix*)
+        AC_DEFINE(GC_THREADS)
+        AC_DEFINE(_REENTRANT)
+        ;;
      *-*-openbsd*)
         AC_DEFINE(GC_THREADS)
         if test "${enable_parallel_mark}" != no; then