See https://groups.google.com/forum/#!topic/minisat/FCocZsC8oMQ
This seems to only be a problem with newer versions of g++, and
upstream development seems to have stopped in 2013.

diff -rupN minisat-2.2.0/core/SolverTypes.h minisat-2.2.0.patched/core/SolverTypes.h
--- a/minisat/core/SolverTypes.h	2010-07-10 17:07:36.000000000 +0100
+++ b/minisat/core/SolverTypes.h	2014-03-29 11:57:49.000000000 +0000
@@ -47,7 +47,7 @@ struct Lit {
     int     x;

     // Use this as a constructor:
-    friend Lit mkLit(Var var, bool sign = false);
+    //friend Lit mkLit(Var var, bool sign = false);

     bool operator == (Lit p) const { return x == p.x; }
     bool operator != (Lit p) const { return x != p.x; }
@@ -55,7 +55,7 @@ struct Lit {
 };


-inline  Lit  mkLit     (Var var, bool sign) { Lit p; p.x = var + var + (int)sign; return p; }
+inline  Lit  mkLit     (Var var, bool sign = false) { Lit p; p.x = var + var + (int)sign; return p; }
 inline  Lit  operator ~(Lit p)              { Lit q; q.x = p.x ^ 1; return q; }
 inline  Lit  operator ^(Lit p, bool b)      { Lit q; q.x = p.x ^ (unsigned int)b; return q; }
 inline  bool sign      (Lit p)              { return p.x & 1; }
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<div class='path'>path: <a href='/guix/log/?id=8b627a77014bc64bae2481fceeb28bcd61035b5b'>root</a>/<a href='/guix/log/build-aux?id=8b627a77014bc64bae2481fceeb28bcd61035b5b'>build-aux</a>/<a href='/guix/log/build-aux/cuirass?id=8b627a77014bc64bae2481fceeb28bcd61035b5b'>cuirass</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/build-aux/cuirass?id=8b627a77014bc64bae2481fceeb28bcd61035b5b&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2021-03-10 19:41:15 +0100'>2021-03-10</span></td><td><a href='/guix/commit/build-aux/cuirass?id=33bb89c939aee88bd211964db600df65d1b656af'>ci: Remove hydra support.</a><span class='msg-avail'>...<span class='msg-tooltip'>This removes hydra support to use Cuirass as the only continuous integration
system.

* build-aux/hydra/gnu-system.scm: Remove it.
* build-aux/hydra/guix-modular.scm: Ditto.
* build-aux/hydra/guix.scm: Ditto.
* build-aux/cuirass/hydra-to-cuirass.scm: Ditto.
* Makefile.am (EXTRA_DIST): Update it.
(hydra-jobs.scm): Remove it.
(cuirass-jobs.scm): Update it.
* build-aux/hydra/evaluate.scm: Move it to ...
* build-aux/cuirass/evaluate.scm: ... here.
* build-aux/cuirass/guix-modular.scm: Remove it.
* build-aux/cuirass/gnu-system.scm: Ditto.
* guix/packages.scm (%hydra-supported-systems): Rename it to ...
(%cuirass-supported-systems): ... this variable.
* build-aux/check-final-inputs-self-contained: Adapt it.
* etc/release-manifest.scm: Ditto.
* gnu/ci.scm (package-&gt;alist): Remove it.
(derivation-&gt;job): New procedure.
(package-job, package-cross-job, cross-jobs, image-jobs, system-test-jobs,
tarball-jobs): Use it.
(guix-jobs): New procedure.
(hydra-jobs): Rename it to ...
(cuirass-jobs): ... this procedure.
</span></span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2020-10-04 14:04:14 +0200'>2020-10-04</span></td><td><a href='/guix/commit/build-aux/cuirass?id=fdbf8a7a75e9d63957ea6d8a63181aa131edeaea'>cuirass: Add hurd-manifest.</a><span class='msg-avail'>...<span class='msg-tooltip'>* build-aux/cuirass/hurd-manifest.scm: New file.
</span></span></td><td>Jan (janneke) Nieuwenhuizen</td></tr>
<tr><td><span title='2018-04-08 17:48:33 +0200'>2018-04-08</span></td><td><a href='/guix/commit/build-aux/cuirass?id=351f384e57939005b25fa976952e3a0e08785893'>cuirass: Add job specs for the modular Guix.</a><span class='msg-avail'>...<span class='msg-tooltip'>* build-aux/cuirass/guix-modular.scm: New file.
* Makefile.am (EXTRA_DIST): Add it.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-04-08 17:48:33 +0200'>2018-04-08</span></td><td><a href='/guix/commit/build-aux/cuirass?id=a1ec7540be9b30593f5e83e36a0e83b1bcf337f1'>cuirass: Factorize hydra-to-cuirass CI job translation.</a><span class='msg-avail'>...<span class='msg-tooltip'>* build-aux/cuirass/gnu-system.scm: Move code to...
* build-aux/cuirass/hydra-to-cuirass.scm: ... here, and include it.
* Makefile.am (EXTRA_DIST): Add 'build-aux/cuirass/hydra-to-cuirass.scm'
and 'build-aux/cuirass/gnu-system.scm'.
</span></span></td><td>Ludovic Courtès</td></tr>