-# Enable silent rules if available (Introduced in AM 1.11)
-m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
-
-AC_REQUIRE_AUX_FILE([tap-driver.sh])
-
-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_HAVE_FENCE], [Defined when on a system that has memory fence instructions.])
-AH_TEMPLATE([CONFIG_RCU_HAVE_FUTEX], [Defined when on a system with futex support.])
-AH_TEMPLATE([CONFIG_RCU_COMPAT_ARCH], [Compatibility mode for i386 which lacks cmpxchg instruction.])
-AH_TEMPLATE([CONFIG_RCU_ARM_HAVE_DMB], [Use the dmb instruction if available for use on ARM.])
-AH_TEMPLATE([CONFIG_RCU_TLS], [TLS provided by the compiler.])
-AH_TEMPLATE([CONFIG_RCU_HAVE_CLOCK_GETTIME], [clock_gettime() is detected.])
-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. Introduce performance penalty.])
-
-# 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=$enableval],
- [def_compiler_tls="yes"])
-
-# If not overridden, use ax_tls.m4 to check if TLS is available.
-AS_IF([test "x$def_compiler_tls" = "xyes"],
- [AX_TLS([def_tls_detect=$ac_cv_tls], [:])],
- [:])
-
-AS_IF([test "x$def_tls_detect" = "x"],
- [:],
- [AC_DEFINE_UNQUOTED([CONFIG_RCU_TLS], $def_tls_detect)])
-
-# Checks for C compiler
-AC_USE_SYSTEM_EXTENSIONS