diff --git a/src/configure b/src/configure
index d305222935..85000e0cf7 100755
--- a/src/configure
+++ b/src/configure
@@ -4093,6 +4093,9 @@ case "$host_os" in
       PREFLAGS="$PREFLAGS -DXONX "
     fi
     ;;
+  nto-qnx*)
+    LIBS="$LIBS -lsocket"
+    ;;
   *)
     ;;
 esac
@@ -5243,7 +5246,7 @@ if test "${enable_backtrace}" = "yes" ; then
 fi
 
 LFS_CFLAGS=`getconf LFS_CFLAGS 2> /dev/null`
-if test "${LFS_CFLAGS}" != "" ; then
+if test "${LFS_CFLAGS}" != "" && test "${LFS_CFLAGS}" != "undefined"; then
   echo "Large-file support: ${LFS_CFLAGS}"
   MZOPTIONS="${MZOPTIONS} ${LFS_CFLAGS}"
 fi
diff --git a/src/racket/configure.ac b/src/racket/configure.ac
index aeb8dbf08a..2700d8176a 100644
--- a/src/racket/configure.ac
+++ b/src/racket/configure.ac
@@ -625,6 +625,9 @@ case "$host_os" in
       PREFLAGS="$PREFLAGS -DXONX "
     fi
     ;;
+  nto-qnx*)
+    LIBS="$LIBS -lsocket"
+    ;;
   *)
     ;;
 esac
@@ -837,7 +840,7 @@ if test "${enable_backtrace}" = "yes" ; then
 fi
 
 LFS_CFLAGS=`getconf LFS_CFLAGS 2> /dev/null`
-if test "${LFS_CFLAGS}" != "" ; then
+if test "${LFS_CFLAGS}" != "" && test "${LFS_CFLAGS}" != "undefined"; then
   echo "Large-file support: ${LFS_CFLAGS}"
   MZOPTIONS="${MZOPTIONS} ${LFS_CFLAGS}"  
 fi
diff --git a/src/racket/gc/include/private/gcconfig.h b/src/racket/gc/include/private/gcconfig.h
index c8e60f3c70..3eb01a4b7f 100644
--- a/src/racket/gc/include/private/gcconfig.h
+++ b/src/racket/gc/include/private/gcconfig.h
@@ -45,6 +45,20 @@
 #  endif
 # endif
 
+/* PLTSCHEME: added QNX: */
+/* And one for QNX: */
+# if defined(__QNX__)
+#    define I386
+#    define OS_TYPE "QNX"
+#    define SA_RESTART 0
+#    define HEURISTIC1
+     extern char etext[];
+#    define DATASTART ((ptr_t)(etext))
+     extern int _end[];
+#    define DATAEND (_end)
+#    define mach_type_known
+# endif
+
 /* And one for NetBSD: */
 # if defined(__NetBSD__)
 #    define NETBSD
diff --git a/src/racket/sconfig.h b/src/racket/sconfig.h
index 54775fb230..d5c5d384c9 100644
--- a/src/racket/sconfig.h
+++ b/src/racket/sconfig.h
@@ -937,6 +937,11 @@
 
 #endif /* end not OSKit */
 
+#if defined(__QNX__)
+# define USE_FCNTL_O_NONBLOCK
+# define SCHEME_PLATFORM_LIBRARY_SUBPATH "i386-QNX"
+#endif
+
 /************** (END KNOWN ARCHITECTURE/SYSTEMS) ****************/
 
 
diff --git a/src/racket/src/file.c b/src/racket/src/file.c
index 27b1349e9b..225fae5a0e 100644
--- a/src/racket/src/file.c
+++ b/src/racket/src/file.c
@@ -4925,6 +4925,8 @@ static Scheme_Object *do_directory_list(int break_ok, int argc, Scheme_Object *a
   while ((e = readdir(dir))) {
 #  ifdef DIRENT_NO_NAMLEN
     nlen = strlen(e->d_name);
+#  elif defined(__QNX__) || defined(__QNXNTO__)
+    nlen = e->d_namelen;
 #  else
     nlen = e->d_namlen;
 #  endif