Index: configure
===================================================================
--- configure	(revision 305581dbced29c2fe6bb06909e03de5f7b8a6b9f)
+++ configure	(revision 41cca44b5b36b35c27f252878c7488107149c20a)
@@ -630,4 +630,6 @@
 GREP
 CPP
+WITH_LIBFIBRE_FALSE
+WITH_LIBFIBRE_TRUE
 RANLIB
 LEXLIB
@@ -5439,4 +5441,54 @@
 
 # Checks for libraries.
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for Fibre::yield in -lfibre" >&5
+$as_echo_n "checking for Fibre::yield in -lfibre... " >&6; }
+if ${ac_cv_lib_fibre_Fibre__yield+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lfibre  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char Fibre::yield ();
+int
+main ()
+{
+return Fibre::yield ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_fibre_Fibre__yield=yes
+else
+  ac_cv_lib_fibre_Fibre__yield=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_fibre_Fibre__yield" >&5
+$as_echo "$ac_cv_lib_fibre_Fibre__yield" >&6; }
+if test "x$ac_cv_lib_fibre_Fibre__yield" = xyes; then :
+  HAVE_LIBFIBRE=1
+else
+  HAVE_LIBFIBRE=0
+fi
+
+ if test "$HAVE_LIBFIBRE" -eq 1; then
+  WITH_LIBFIBRE_TRUE=
+  WITH_LIBFIBRE_FALSE='#'
+else
+  WITH_LIBFIBRE_TRUE='#'
+  WITH_LIBFIBRE_FALSE=
+fi
+
 
 # Checks for header files.
@@ -6478,4 +6530,8 @@
 if test -z "${am__fastdepCCAS_TRUE}" && test -z "${am__fastdepCCAS_FALSE}"; then
   as_fn_error $? "conditional \"am__fastdepCCAS\" was never defined.
+Usually this means the macro was only invoked conditionally." "$LINENO" 5
+fi
+if test -z "${WITH_LIBFIBRE_TRUE}" && test -z "${WITH_LIBFIBRE_FALSE}"; then
+  as_fn_error $? "conditional \"WITH_LIBFIBRE\" was never defined.
 Usually this means the macro was only invoked conditionally." "$LINENO" 5
 fi