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; }
/a><a class='active' href='/guix/log/etc/substitutes/berlin.guix.gnu.org.pub'>log</a><a href='/guix/tree/etc/substitutes/berlin.guix.gnu.org.pub?id=8aaf538abb169be39470065ac13d8121f1729c5f'>tree</a><a href='/guix/commit/etc/substitutes/berlin.guix.gnu.org.pub?id=8aaf538abb169be39470065ac13d8121f1729c5f'>commit</a><a href='/guix/diff/etc/substitutes/berlin.guix.gnu.org.pub?id=8aaf538abb169be39470065ac13d8121f1729c5f'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/etc/substitutes/berlin.guix.gnu.org.pub'>
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<div class='path'>path: <a href='/guix/log/?id=8aaf538abb169be39470065ac13d8121f1729c5f'>root</a>/<a href='/guix/log/etc?id=8aaf538abb169be39470065ac13d8121f1729c5f'>etc</a>/<a href='/guix/log/etc/substitutes?id=8aaf538abb169be39470065ac13d8121f1729c5f'>substitutes</a>/<a href='/guix/log/etc/substitutes/berlin.guix.gnu.org.pub?id=8aaf538abb169be39470065ac13d8121f1729c5f'>berlin.guix.gnu.org.pub</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/etc/substitutes/berlin.guix.gnu.org.pub?id=8aaf538abb169be39470065ac13d8121f1729c5f&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-07-10 00:11:00 +0200'>2020-07-10</span></td><td><a href='/guix/commit/etc/substitutes/berlin.guix.gnu.org.pub?id=d283bb960f927dd5f7bb8b96bc697221e4e8ad39'>maint: Remove traces of "berlin.guixsd.org".</a><span class='msg-avail'>...<span class='msg-tooltip'>The guixsd.org domain is no longer advertised since before in 1.0.0
release in May 2019.

* etc/substitutes/berlin.guixsd.org.pub: Rename to...
* etc/substitutes/berlin.guix.gnu.org.pub: ... this.
* etc/substitutes/ci.guix.gnu.org.pub,
etc/substitutes/ci.guix.info.pub: Adjust accordingly.
* gnu/services/base.scm (%default-authorized-guix-keys): Likewise.
* guix/build/download-nar.scm (urls-for-item): Likewise.
* guix/self.scm (miscellaneous-files): Likewise.
* Makefile.am (dist_pkgdata_DATA): Likewise.
</span></span></td><td>Ludovic Courtès</td></tr>