-# Search for clock_gettime
-AC_SEARCH_LIBS([clock_gettime], [rt], [
- AC_DEFINE([CONFIG_RCU_HAVE_CLOCK_GETTIME], [1])
- config_rcu_have_clock_gettime=yes
-], [])
+
+AH_TEMPLATE([CONFIG_RCU_SMP], [Enable SMP support. With SMP support enabled, uniprocessors are also supported. With SMP support disabled, UP systems work fine, but the behavior of SMP systems is undefined.])
+AH_TEMPLATE([CONFIG_RCU_TLS], [TLS provided by the compiler.])
+AH_TEMPLATE([CONFIG_RCU_FORCE_SYS_MEMBARRIER], [Require the operating system to support the membarrier system call for default and bulletproof flavors.])
+AH_TEMPLATE([CONFIG_RCU_DEBUG], [Enable internal debugging self-checks. Introduces a performance penalty.])
+AH_TEMPLATE([CONFIG_CDS_LFHT_ITER_DEBUG], [Enable extra debugging checks for lock-free hash table iterator traversal. Alters the rculfhash ABI. Make sure to compile both library and application with matching configuration.])
+
+# Allow requiring the operating system to support the membarrier system
+# call. Applies to default and bulletproof flavors.
+AC_ARG_ENABLE([sys-membarrier-fallback],
+ AS_HELP_STRING([--disable-sys-membarrier-fallback], [Abort if sys-membarrier is needed but not available rather than using a fallback.]),
+ [def_sys_membarrier_fallback=$enableval],
+ [def_sys_membarrier_fallback="yes"])
+AS_IF([test "x$def_sys_membarrier_fallback" != "xyes"], [AC_DEFINE([CONFIG_RCU_FORCE_SYS_MEMBARRIER], [1])])
+
+# Allow overriding storage used for TLS variables.
+AC_ARG_ENABLE([compiler-tls],
+ AS_HELP_STRING([--disable-compiler-tls], [Use pthread_getspecific() to emulate Thread Local Storage (TLS) variables.]),
+ [def_compiler_tls=$enableval],
+ [def_compiler_tls="yes"])
+
+AS_IF([test "x$def_compiler_tls" = "xyes"], AC_DEFINE([CONFIG_RCU_TLS], [1]), [:])
+
+
+AM_CFLAGS="$AM_CFLAGS $PTHREAD_CFLAGS"