fix apple silicon build, bump version ngalpaha.5

Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "ng-rocksdb"
 description = "Rust wrapper for Facebook's RocksDB embeddable database, fork for Nextgraph.org"
-version = "0.21.0-ngpreview.4"
+version = "0.21.0-ngalpha.5"
 edition = "2018"
 rust-version = "1.60"
 authors = ["Tyler Neely <t@jujit.su>", "David Greenberg <dsg123456789@gmail.com>"]

librocksdb-sys/build.rs

@@ -196,7 +196,9 @@ fn build_rocksdb() {
         config.define("ROCKSDB_LIB_IO_POSIX", None);
         env::set_var("IPHONEOS_DEPLOYMENT_TARGET", "12.0");
     } else if target.contains("darwin") {
-        config.flag("-march=haswell");
+        if !target.contains("aarch64-apple-darwin") {
+            config.flag("-march=haswell");
+        }
         config.define("OS_MACOSX", None);
         config.define("ROCKSDB_PLATFORM_POSIX", None);
         config.define("ROCKSDB_LIB_IO_POSIX", None);