Description: Raise ProcessorAutodetectError for unknown machine names
 Previously this function was only used for the JIT, so it only had to support
 machines that the JIT supports.
 Now, it's used by rpython.rlib.rawstorage, and should raise an appropriate
 exception, rather than KeyError, on unknown machines.
Author: Stefano Rivera <stefanor@debian.org>

--- a/rpython/jit/backend/detect_cpu.py
+++ b/rpython/jit/backend/detect_cpu.py
@@ -63,7 +63,10 @@
             'AMD64': MODEL_X86,    # win64
             'armv7l': MODEL_ARM,
             'armv6l': MODEL_ARM,
-            }[mach]
+            }.get(mach)
+
+    if result is None:
+        raise ProcessorAutodetectError, "unknown machine name %s" % mach
     #
     if result.startswith('x86'):
         if sys.maxint == 2**63-1:
