Merge pull request #4169 from felixonmars/patch-1

Use defined variable for riscv64 in arch.cmake

Author: martin-frbg

cmake/arch.cmake

@@ -135,7 +135,7 @@ if (ARM64)
   set(BINARY_DEFINED 1)
 endif ()
 
-if (${ARCH} STREQUAL "riscv64")
+if (RISCV64)
   set(NO_BINARY_MODE 1)
   set(BINARY_DEFINED 1)
 endif ()