minisat: fix build

Patch away the strang friend constructor and instead add a default
value to the mkLit() inline function.

srcpkgs/minisat/patches/friend.patch

@@ -0,0 +1,21 @@
+--- core/SolverTypes.h	2010-07-10 18:07:36.000000000 +0200
++++ core/SolverTypes.h	2020-05-27 14:12:09.005969769 +0200
+@@ -46,8 +46,8 @@
+ struct Lit {
+     int     x;
+ 
+     // Use this as a constructor:
+-    friend Lit mkLit(Var var, bool sign = false);
++    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 @@
+ };
+ 
+ 
+-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; }

srcpkgs/minisat/template

@@ -1,7 +1,7 @@
 # Template file for 'minisat'
 pkgname=minisat
 version=2.2.0
-revision=1
+revision=2
 wrksrc=minisat
 build_wrksrc=simp
 build_style=gnu-makefile