Restore compatibility with newer version of base16-bytestring.

Taken from https://raw.githubusercontent.com/archlinux/svntogit-community/packages/trunk/cabal-install-base16-bytestring1.0.patch

diff --git a/Distribution/Client/HashValue.hs b/Distribution/Client/HashValue.hs
index 54b8aee9e..11e647c1c 100644
--- a/Distribution/Client/HashValue.hs
+++ b/Distribution/Client/HashValue.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE CPP          #-}
 {-# LANGUAGE DeriveDataTypeable #-}
 {-# LANGUAGE DeriveGeneric      #-}
 module Distribution.Client.HashValue (
@@ -72,10 +73,14 @@ hashFromTUF (Sec.Hash hashstr) =
     --TODO: [code cleanup] either we should get TUF to use raw bytestrings or
     -- perhaps we should also just use a base16 string as the internal rep.
     case Base16.decode (BS.pack hashstr) of
+#if MIN_VERSION_base16_bytestring(1,0,0)
+      Right hash -> HashValue hash
+      Left _ -> error "hashFromTUF: cannot decode base16"
+#else
       (hash, trailing) | not (BS.null hash) && BS.null trailing
         -> HashValue hash
       _ -> error "hashFromTUF: cannot decode base16 hash"
-
+#endif
 
 -- | Truncate a 32 byte SHA256 hash to
 --
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<tr><th>author</th><td>Leo Famulari &lt;leo@famulari.name&gt;</td><td class='right'>2016-07-19 23:59:22 -0400</td></tr>
<tr><th>committer</th><td>Leo Famulari &lt;leo@famulari.name&gt;</td><td class='right'>2016-07-20 00:01:39 -0400</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/guix/commit/tests/services.scm?id=5d4c90ae02f1e0b42d575bba2d828d63aaf79be5'>5d4c90ae02f1e0b42d575bba2d828d63aaf79be5</a> (<a href='/guix/patch/tests/services.scm?id=5d4c90ae02f1e0b42d575bba2d828d63aaf79be5'>patch</a>)</td></tr>
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<tr><th>parent</th><td colspan='2' class='oid'><a href='/guix/commit/tests/services.scm?id=91f9f33a195b20a7b0501da201cec45ff7e9c558'>91f9f33a195b20a7b0501da201cec45ff7e9c558</a> (<a href='/guix/diff/tests/services.scm?id=5d4c90ae02f1e0b42d575bba2d828d63aaf79be5&amp;id2=91f9f33a195b20a7b0501da201cec45ff7e9c558'>diff</a>)</td></tr><tr><th>download</th><td colspan='2' class='oid'><a href='/guix/snapshot/guix-5d4c90ae02f1e0b42d575bba2d828d63aaf79be5.tar.gz'>guix-5d4c90ae02f1e0b42d575bba2d828d63aaf79be5.tar.gz</a><br/><a href='/guix/snapshot/guix-5d4c90ae02f1e0b42d575bba2d828d63aaf79be5.zip'>guix-5d4c90ae02f1e0b42d575bba2d828d63aaf79be5.zip</a><br/></td></tr></table>
<div class='commit-subject'>gnu: gnutls: Update to 3.5.2.</div><div class='commit-msg'>* gnu/packages/tls.scm (gnutls): Update to 3.5.2.
[native-inputs]: Add net-tools.
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