cgdb: fix compilation with GCC 14

See https://github.com/cgdb/cgdb/pull/368 for the upstream pull request.

pkgs/by-name/cg/cgdb/gcc14.patch

@@ -0,0 +1,13 @@
+diff --git a/configure b/configure
+index c564dc1..e13c67c 100755
+--- a/configure
++++ b/configure
+@@ -6512,7 +6512,7 @@ else
+ #include <stdlib.h>
+ #include <readline/readline.h>
+ 
+-main()
++int main()
+ {
+ 	FILE *fp;
+ 	fp = fopen("conftest.rlv", "w");

pkgs/by-name/cg/cgdb/package.nix

@@ -17,6 +17,10 @@ stdenv.mkDerivation (finalAttrs: {
     sha256 = "sha256-DTi1JNN3JXsQa61thW2K4zBBQOHuJAhTQ+bd8bZYEfE=";
   };
 
+  patches = [
+    ./gcc14.patch
+  ];
+
   buildInputs = [
     ncurses
     readline