diff --git a/racket/src/configure b/racket/src/configure
index ab1d1f3048..59ea436074 100755
--- a/racket/src/configure
+++ b/racket/src/configure
@@ -4470,17 +4470,17 @@ case "$host_os" in
   *freebsd*)
     LIBS="$LIBS -rdynamic"
     DYN_CFLAGS="-fPIC"
-    enable_pthread=yes
+    enable_pthread_by_default=yes
     try_kqueue_syscall=yes
     ;;
   openbsd*)
     LIBS="$LIBS -Wl,--export-dynamic"
-    enable_pthread=yes
+    enable_pthread_by_default=yes
     try_kqueue_syscall=yes
     ;;
   dragonfly*)
     LIBS="$LIBS -Wl,--export-dynamic"
-    enable_pthread=yes
+    enable_pthread_by_default=yes
     try_kqueue_syscall=yes
     ;;
   netbsd*)
@@ -6256,6 +6256,12 @@ fi
 
 ############### pthread ###################
 
+if test "${enable_pthread}" = "" ; then
+  if test "${enable_pthread_by_default}" = "yes" ; then
+    enable_pthread=yes
+  fi
+fi
+
 if test "${enable_pthread}" = "yes" ; then
   if test "${use_flag_pthread}" = "yes" ; then
     PREFLAGS="$PREFLAGS -pthread"
diff --git a/racket/src/racket/configure.ac b/racket/src/racket/configure.ac
index 07777def6a..a37a060234 100644
--- a/racket/src/racket/configure.ac
+++ b/racket/src/racket/configure.ac
@@ -614,17 +614,17 @@ case "$host_os" in
   *freebsd*)
     LIBS="$LIBS -rdynamic"
     DYN_CFLAGS="-fPIC"
-    enable_pthread=yes
+    enable_pthread_by_default=yes
     try_kqueue_syscall=yes
     ;;
   openbsd*)
     LIBS="$LIBS -Wl,--export-dynamic"
-    enable_pthread=yes
+    enable_pthread_by_default=yes
     try_kqueue_syscall=yes
     ;;
   dragonfly*)
     LIBS="$LIBS -Wl,--export-dynamic"
-    enable_pthread=yes
+    enable_pthread_by_default=yes
     try_kqueue_syscall=yes
     ;;
   netbsd*)
@@ -1276,6 +1276,12 @@ fi
 
 ############### pthread ###################
 
+if test "${enable_pthread}" = "" ; then
+  if test "${enable_pthread_by_default}" = "yes" ; then
+    enable_pthread=yes
+  fi
+fi
+
 if test "${enable_pthread}" = "yes" ; then
   if test "${use_flag_pthread}" = "yes" ; then
     PREFLAGS="$PREFLAGS -pthread"