openocd: fix build with gcc 11

Werror should not be used when packaging

Changed files
+1
pkgs
development
embedded
openocd
+1
pkgs/development/embedded/openocd/default.nix
···
];
configureFlags = [
+
"--disable-werror"
"--enable-jtag_vpi"
"--enable-usb_blaster_libftdi"
(lib.enableFeature (! stdenv.isDarwin) "amtjtagaccel")