Add more openbsd archs

Index: compiler/rustc_target/src/spec/mod.rs
--- compiler/rustc_target/src/spec/mod.rs.orig
+++ compiler/rustc_target/src/spec/mod.rs
@@ -890,9 +890,11 @@ supported_targets! {
 
     ("aarch64-unknown-openbsd", aarch64_unknown_openbsd),
     ("i686-unknown-openbsd", i686_unknown_openbsd),
+    ("powerpc-unknown-openbsd", powerpc_unknown_openbsd),
+    ("powerpc64-unknown-openbsd", powerpc64_unknown_openbsd),
+    ("riscv64-unknown-openbsd", riscv64_unknown_openbsd),
     ("sparc64-unknown-openbsd", sparc64_unknown_openbsd),
     ("x86_64-unknown-openbsd", x86_64_unknown_openbsd),
-    ("powerpc-unknown-openbsd", powerpc_unknown_openbsd),
 
     ("aarch64-unknown-netbsd", aarch64_unknown_netbsd),
     ("armv6-unknown-netbsd-eabihf", armv6_unknown_netbsd_eabihf),
