games/openenroth: update OpenEnroth to the latest pre-SDL3 commit

• Unbreak the build against modern FFmpeg versions
• The code requires C++23 so remove now helpless hacks
• Follow-up commit 29a23b8db460 and replace LLD_UNSAFE with the more appropriate LDFLAGS_i386=-Wl,-znotext
• Add PORTSCOUT to ignore not particularly useful tag
• Shaders are now embedded in the executable itself
• Install two extra programs for developers/modders