New test tool: list-accel.py.

Gives a quick and easy report of which HW-accelerated crypto
implementations are (a) compiled in to testcrypt, (b) actually
instantiable at testcrypt run time.

test/list-accel.py

@@ -0,0 +1,34 @@
+#!/usr/bin/env python3
+
+# Simple client of the testcrypt system that reports the available
+# variants of each of the crypto primitives that have hardware-
+# accelerated implementations.
+#
+# It will report the set of primitives compiled in to testcrypt, and
+# also report whether each one can be instantiated at run time.
+
+from testcrypt import *
+
+def get_implementations(alg):
+    return get_implementations_commasep(alg).decode("ASCII").split(",")
+
+def list_implementations(alg, checkfn):
+    print(f"Implementations of {alg}:")
+    for impl in get_implementations(alg):
+        if impl == alg:
+            continue
+        if checkfn(impl):
+            print(f"  {impl:<32s} available")
+        else:
+            print(f"  {impl:<32s} compiled in, but unavailable at run time")
+
+def list_cipher_implementations(alg):
+    list_implementations(alg, lambda impl: ssh_cipher_new(impl) is not None)
+
+def list_hash_implementations(alg):
+    list_implementations(alg, lambda impl: ssh_hash_new(impl) is not None)
+
+list_cipher_implementations("aes256_cbc")
+list_hash_implementations("sha1")
+list_hash_implementations("sha256")
+list_hash_implementations("sha512")