--- a/build/moz.configure/rust.configure
+++ b/build/moz.configure/rust.configure
@@ -146,16 +146,19 @@ def rust_triple_alias(host_or_target):
             ('x86', 'OpenBSD'): 'i686-unknown-openbsd',
             ('x86_64', 'OpenBSD'): 'x86_64-unknown-openbsd',
             # Linux
             ('aarch64', 'Linux'): 'aarch64-unknown-linux-gnu',
             ('arm', 'Linux'): 'armv7-unknown-linux-gnueabihf',
             ('sparc64', 'Linux'): 'sparc64-unknown-linux-gnu',
             ('x86', 'Linux'): 'i686-unknown-linux-gnu',
             ('x86_64', 'Linux'): 'x86_64-unknown-linux-gnu',
+            ('ppc64le', 'Linux'): 'powerpc64le-unknown-linux-gnu',
+            ('ppc64', 'Linux'): 'powerpc64-unknown-linux-gnu',
+            ('s390x', 'Linux'): 's390x-unknown-linux-gnu',
             # OS X
             ('x86', 'OSX'): 'i686-apple-darwin',
             ('x86_64', 'OSX'): 'x86_64-apple-darwin',
             # iOS
             ('aarch64', 'iOS'): 'aarch64-apple-ios',
             ('arm', 'iOS'): 'armv7s-apple-ios',
             ('x86', 'iOS'): 'i386-apple-ios',
             ('x86_64', 'iOS'): 'x86_64-apple-ios',
@@ -170,17 +173,17 @@ def rust_triple_alias(host_or_target):
             ('x86', 'WINNT-MINGW'): 'i686-pc-windows-gnu',
             ('x86_64', 'WINNT-MINGW'): 'x86_64-pc-windows-gnu',
             # Solaris
             ('x86_64', 'SunOS'): 'x86_64-sun-solaris',
             ('sparc64', 'SunOS'): 'sparcv9-sun-solaris',
         }.get((host_or_target.cpu, os_or_kernel), None)
 
         if rustc_target is None:
-            die("Don't know how to translate {} for rustc".format(host_or_target.alias))
+            die("Don't know how to translate {} for rustc, cpu: {}, os: {}".format(target.alias, target.cpu, os_or_kernel))
 
         # Check to see whether our rustc has a reasonably functional stdlib
         # for our chosen target.
         target_arg = '--target=' + rustc_target
         in_fd, in_path = mkstemp(prefix='conftest', suffix='.rs')
         out_fd, out_path = mkstemp(prefix='conftest', suffix='.rlib')
         os.close(out_fd)
         try: