x11/contour: Update to 0.6.2.8008

While here, add patch to fix build with clang/libc++ 19.

libc++ 19 only provides std::char_traits for character types, which
causes compile errors when crispy::fnv is instantiated with non-char
types.

Restricting string-related overloads to char-only types, and adding a
generic trivially-copyable value hashing overload restore successful
builds on clang/libc++ 19.

Changelog: https://github.com/contour-terminal/contour/releases/tag/v0.6.2.8008

Reported by: portscout