libcamera: disable blanket -Werror

`-Werror` flag usually causes build failures due to minor changes in
compiler versions. They might be useful for developers themselves but
are rarely useful for distributions.

For example right now `libcamera` fails to compile on `gcc-13` due to a
`gcc` infelicity: https://gcc.gnu.org/PR107488

While this concrete instance is a compiler bug generally `-Werror` makes
users' lives harder. Specific `-Werror=<foo>` are better way to prevent
certain classes of bugs.

The change removes planket `-Werror` with `-Dwerror=false` flag.

pkgs/development/libraries/libcamera/default.nix

@@ -77,6 +77,9 @@ stdenv.mkDerivation rec {
     "-Dv4l2=true"
     "-Dqcam=disabled"
     "-Dlc-compliance=disabled" # tries unconditionally to download gtest when enabled
+    # Avoid blanket -Werror to evade build failures on less
+    # tested compilers.
+    "-Dwerror=false"
     ];
 
   # Fixes error on a deprecated declaration