This patch resolves a build failure when building TopHat 2.1.0 with SeqAn 1.4.
This is the relevant part of a patch originally posted here:
https://lists.fu-berlin.de/pipermail/seqan-dev/2014-July/msg00001.html

--- a/src/segment_juncs.cpp
+++ b/src/segment_juncs.cpp
@@ -2050,10 +2050,13 @@ void juncs_from_ref_segs(RefSequenceTabl
     typedef map<uint32_t, IntronMotifs> MotifMap;
     
     MotifMap ims;
-	
-    seqan::DnaStringReverseComplement rev_donor_dinuc(donor_dinuc);
-    seqan::DnaStringReverseComplement rev_acceptor_dinuc(acceptor_dinuc);
-    
+
+    typedef seqan::ModifiedString<
+                    seqan::ModifiedString<seqan::DnaString const, seqan::ModView<seqan::FunctorComplement<seqan::Dna> > >,  
+                    seqan::ModReverse>   ConstDnaStringReverseComplement;
+    ConstDnaStringReverseComplement rev_donor_dinuc(donor_dinuc);
+    ConstDnaStringReverseComplement rev_acceptor_dinuc(acceptor_dinuc);
+     
     if (talkative)
         fprintf(stderr, "Collecting potential splice sites in islands\n");
 
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<div class='path'>path: <a href='/guix/log/?id=abeb985d4cd158e3c05b6065716af24e8d31cd7c'>root</a>/<a href='/guix/log/m4?id=abeb985d4cd158e3c05b6065716af24e8d31cd7c'>m4</a>/<a href='/guix/log/m4/guix.m4?id=abeb985d4cd158e3c05b6065716af24e8d31cd7c'>guix.m4</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/m4/guix.m4?id=abeb985d4cd158e3c05b6065716af24e8d31cd7c&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-01-14 11:41:15 +0200'>2022-01-14</span></td><td><a href='/guix/commit/m4/guix.m4?id=03b45230d409c5f09e6ad18f23f313a13dbddb7d'>gnu: bootstrap: Add support for riscv64-linux.</a><span class='msg-avail'>...<span class='msg-tooltip'>On 7d93b21ab1c132990054372a9677c1639d54e631
    gnu: glibc-for-bootstrap: Update patch.

Run
    ./pre-inst-env guix build --target=riscv64-linux-gnu bootstrap-tarballs

Producing
    /gnu/store/4hdzva9i0wyyfbgj1lmqc1wkk644pv07-bootstrap-tarballs-0

With guix hash -rx
    1nj0fdgj08bbmfny01mp2blv7c3p2iciqh31zmf04ap5s7ygsqlp

* gnu/packages/bootstrap.scm (%bootstrap-executables): Add entries for
riscv64-linux.
(%bootstrap-guile-hash, %bootstrap-coreutils&amp;co, %bootstrap-binutils,
%bootstrap-glibc, %bootstrap-gcc): Add entry for riscv64-linux.
(raw-build-guile3): New procedure.
(make-raw-bag): Use raw-build-guile3 for riscv64-linux.
* guix/packages.scm (%supported-systems): Add riscv64-linux.
(%cuirass-supported-systems): Remove riscv64-linux.
* guix/utils.scm (target-64bit?): Add riscv64-linux.
* m4/guix.m4: Add riscv64-linux as a supported system.
* doc/guix.texi (GNU Distribution): Add riscv64-linux.
</span></span></td><td>Efraim Flashner</td></tr>