Add riscv64 define for cds

Author: Xeonacid

extern/libcds/cds/compiler/gcc/compiler_macro.h

@@ -132,6 +132,11 @@
 #   define CDS_PROCESSOR__NAME   "LOONGARCH"
 #   define CDS_PROCESSOR__NICK   "loongarch"
 #   define CDS_BUILD_BITS        64
+#elif defined(__riscv) && __riscv_xlen == 64
+#   define CDS_PROCESSOR_ARCH    CDS_PROCESSOR_RISCV64
+#   define CDS_PROCESSOR__NAME   "RISC-V64"
+#   define CDS_PROCESSOR__NICK   "riscv64"
+#   define CDS_BUILD_BITS        64
 #else
 #   if defined(CDS_USE_LIBCDS_ATOMIC)
 #       error "Libcds does not support atomic implementation for the processor architecture. Try to use C++11-compatible compiler and remove CDS_USE_LIBCDS_ATOMIC flag from compiler command line"