sgfutils: fix gcc-15 build

Without the chnage the build fails on `master` as:

```
sgfinfo.c: In function 'report_on_single_game':
sgfinfo.c:948:27: error: assignment to 'void (*)(void)' from incompatible pointer type 'void (*)(int)' [-Wincompatible-pointer-types]
  948 |                 outmovefn = fns[(optM-1) % 3];
      |                           ^
sgfinfo.c:952:25: error: too many arguments to function 'outmovefn'; expected 0, have 1
  952 |                         outmovefn(i);
      |                         ^~~~~~~~~ ~
```

pkgs/by-name/sg/sgfutils/gcc-15.patch

@@ -0,0 +1,26 @@
+Generated as:
+$ curl -L https://github.com/yangboz/sgfutils/pull/3.diff > gcc-15.patch
+
+Fix `gcc-15` build failure related to `c23` changes.
+--- a/gib2sgf.c
++++ b/gib2sgf.c
+@@ -433,7 +433,7 @@ static void stoline(char *buf) {
+ 	readmove(buf);
+ }
+ 
+-static void (*inputline[])() = {
++static void (*inputline[])(char*) = {
+ 	inline0, inline1, iniline, stoline
+ };
+ 
+--- a/sgfinfo.c
++++ b/sgfinfo.c
+@@ -940,7 +940,7 @@ void report_on_single_game() {
+ 	if (optM) {
+ 		int imin, imax;
+ 		void (*fns[3])(int) = { outmove, outmovec, outmovex };
+-		void (*outmovefn)();
++		void (*outmovefn)(int);
+ 
+ 		/* 1..3 moves / 4..6 init / 7..9 both */
+ 		imin = ((optM < 4) ? initct : 0);

pkgs/by-name/sg/sgfutils/package.nix

@@ -17,6 +17,10 @@ stdenv.mkDerivation {
     rev = "11ab171c46cc16cc71ac6fc901d38ea88d6532a4";
     hash = "sha256-KWYgTxz32WK3MKouj1WAJtZmleKt5giCpzQPwfWruZQ=";
   };
+  patches = [
+    # FIx gcc-15 build failure: https://github.com/yangboz/sgfutils/pull/3
+    ./gcc-15.patch
+  ];
   nativeBuildInputs = [ makeWrapper ];
   buildInputs = [ openssl ] ++ lib.optionals stdenv.hostPlatform.isDarwin [ libiconv ];
   buildPhase = ''