+Usage of liburcu-mb
+
+ * #include <urcu.h>
+ * Compile any _LGPL_SOURCE code using this library with "-DRCU_MB".
+ * Link with "-lurcu-mb".
+ * This version of the urcu library uses memory barriers on the writer
+ and reader sides. This results in faster grace-period detection, but
+ results in slower reads.
+
+Usage of liburcu-signal
+
+ * #include <urcu.h>
+ * Compile any _LGPL_SOURCE code using this library with "-DRCU_SIGNAL".
+ * Link the application with "-lurcu-signal".
+ * Version of the library that requires a signal, typically SIGUSR1. Can
+ be overridden with -DSIGRCU by modifying Makefile.build.inc.
+