libg15render: add standard headers to fix build with GCC 14

pkgs/by-name/g1/g15daemon/libg15render-implicit-decls.patch

@@ -0,0 +1,15 @@
+diff --git a/pixel.c b/pixel.c
+
+--- a/pixel.c
++++ b/pixel.c
+@@ -19,6 +19,10 @@
+ #include <fcntl.h>
+ #include "libg15render.h"
+
++#include <math.h>
++#include <stdlib.h>
++#include <unistd.h>
++
+ void
+ swap (int *x, int *y)
+ {

pkgs/by-name/g1/g15daemon/package.nix

@@ -47,6 +47,10 @@ let
       sha256 = "03yjb78j1fnr2fwklxy54sdljwi0imvp29m8kmwl9v0pdapka8yj";
     };
 
+    patches = [
+      ./libg15render-implicit-decls.patch
+    ];
+
     buildInputs = [ libg15 ];
 
     enableParallelBuilding = true;