Support old CPUs (#22)

* build: set `PORTABLE = ON` for every target

* build: allow setting PORTABLE=OFF via env var

* rocksdb-sys: bump version to 0.5.3

rocksdb-sys/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "parity-rocksdb-sys"
-version = "0.5.2"
+version = "0.5.3"
 authors = ["Tyler Neely <t@jujit.su>", "David Greenberg <dsg123456789@gmail.com>", "Parity Technologies <admin@parity.io>"]
 license = "MIT/Apache-2.0/BSD-3-Clause"
 description = "Native bindings to librocksdb"

rocksdb-sys/build.rs

@@ -43,7 +43,13 @@ fn main() {
     let target_arch = env::var("CARGO_CFG_TARGET_ARCH")
         .expect("CARGO_CFG_TARGET_ARCH is set by cargo.");
 
-    if target_arch == "arm" || target_arch == "aarch64" {
+    // Added to support old CPUs
+    // see https://github.com/paritytech/parity-ethereum/issues/9684
+    let portable = match &*env::var("PORTABLE").unwrap_or("ON".to_owned()) {
+        "OFF" => false,
+        _ => true,
+    };
+    if portable {
         cfg.define("PORTABLE", "ON");
     }