diff -ru bdwgc.orig/configure.ac bdwgc/configure.ac
--- bdwgc.orig/configure.ac	2020-07-05 12:09:58.042430329 +0200
+++ bdwgc/configure.ac	2020-07-06 19:34:20.918143543 +0200
@@ -194,7 +194,7 @@
       *-*-aix* | *-*-android* | *-*-cygwin* | *-*-darwin* | *-*-dragonfly* | \
       *-*-freebsd* | *-*-haiku* | *-*-hpux11* | *-*-irix* | \
       *-*-kfreebsd*-gnu | *-*-gnu* | *-*-*linux* | *-*-msys* | *-*-nacl* | \
-      *-*-netbsd* | *-*-openbsd* | *-*-osf* | *-*-solaris*)
+      *-*-netbsd* | *-*-openbsd* | *-*-osf* | *-*-solaris* | *-*-midipix*)
         AC_DEFINE(GC_THREADS)
         AC_DEFINE([_REENTRANT], [1],
                   [Required define if using POSIX threads.])
@@ -240,6 +240,10 @@
         THREADDLLIBS=""
         win32_threads=true
         ;;
+      *-*-midipix*)
+        # libpthread is part of libc
+        THREADDLLIBS=""
+        ;;
       *-*-mingw*)
         AC_DEFINE(GC_WIN32_PTHREADS)
         # Using pthreads-win32 (or other non-Cygwin pthreads) library.
@@ -791,7 +795,7 @@
        [AC_TRY_COMPILE([
 #ifdef __CYGWIN__
 #define _GNU_SOURCE 1
-#elif defined(__linux__) || defined(__GLIBC__) || defined(__GNU__)
+#elif defined(__linux__) || defined(__GLIBC__) || defined(__GNU__) || defined(__midipix__)
 #define _GNU_SOURCE 1
 #endif
 #include <pthread.h>],