math/singular: Fix build on 15; Update WWW

Reported by:	fallout

math/singular/Makefile

@@ -8,7 +8,8 @@ DIST_SUBDIR=	${PORTNAME}
 
 MAINTAINER=	yuri@FreeBSD.org
 COMMENT=	Computer algebra system for polynomial computations
-WWW=		https://www.singular.uni-kl.de/
+WWW=		https://www.singular.uni-kl.de/ \
+		https://github.com/Singular/Singular
 
 LICENSE=	GPLv3RLE
 LICENSE_FILE=	${WRKSRC}/COPYING

math/singular/files/patch-gfanlib_gfanlib__matrix.h

@@ -0,0 +1,18 @@
+--- gfanlib/gfanlib_matrix.h.orig	2024-12-18 20:07:20 UTC
++++ gfanlib/gfanlib_matrix.h
+@@ -115,6 +115,7 @@ template <class typ> class Matrix{ (public)
+                   p[i][j]=s*(q[i][j]);
+       return p;
+     }
++  /*
+   friend Matrix operator*(const Matrix& a, const Matrix& b)
+     {
+       assert(a.width==b.height);
+@@ -123,6 +124,7 @@ template <class typ> class Matrix{ (public)
+         ret[i]=a.vectormultiply(b.column(i));
+       return ret.transposed();
+     }
++  */
+   /*  template<class T>
+     Matrix<T>(const Matrix<T>& c):v(c.size()){
+     for(int i=0;i<size();i++)v[i]=typ(c[i]);}