fix(Defines): also check for _M_RISCV64

The patch submitted by Bo in https://bugs.debian.org/1015787 and zyantific#48
also checked for this additional define, but it was not part of
3e95307. This patch adds the
additional check.

Co-authored-by: Bo YU <[email protected]>

Author: Tachi107

include/Zycore/Defines.h

@@ -140,7 +140,7 @@
 #   define ZYAN_PPC64
 #elif defined(__powerpc__)
 #   define ZYAN_PPC
-#elif defined(__riscv) && __riscv_xlen == 64
+#elif defined(_M_RISCV64) || defined(__riscv) && __riscv_xlen == 64
 #   define ZYAN_RISCV64
 #else
 #   error "Unsupported architecture detected"