Add platform triple arm-unknown-linux-musleabi

Author: martin4861

rust/platform/triple_mappings.bzl

@@ -49,6 +49,7 @@ SUPPORTED_T2_PLATFORM_TRIPLES = {
     "aarch64-unknown-fuchsia": _support(std = True, host_tools = False),
     "aarch64-unknown-uefi": _support(std = True, host_tools = False),
     "arm-unknown-linux-gnueabi": _support(std = True, host_tools = True),
+    "arm-unknown-linux-musleabi": _support(std = True, host_tools = True),
     "armv7-linux-androideabi": _support(std = True, host_tools = False),
     "armv7-unknown-linux-gnueabi": _support(std = True, host_tools = True),
     "i686-linux-android": _support(std = True, host_tools = False),