chore: bump TinyCC to latest upstream (Jan 2026) (#26210)

## What does this PR do?

Updates the oven-sh/tinycc fork to the latest upstream TinyCC,
incorporating 30+ upstream commits while preserving all Bun-specific
patches.

### Upstream changes incorporated
- Build system improvements (c2str.exe handling, cross-compilation)
- macOS 15 compatibility fixes
- libtcc debugging support
- pic/pie support for i386
- arm64 alignment and symbol offset fixes
- RISC-V 64 improvements (pointer difference, assembly, Zicsr extension)
- Relocation updates
- Preprocessor improvements (integer literal overflow handling)
- x86-64 cvts*2si fix
- Various bug fixes

### Bun-specific patches preserved
- Fix crash on macOS x64 (libxcselect.dylib memory handling)
- Implement `-framework FrameworkName` on macOS (for framework header
parsing)
- Add missing #ifdef guards for TCC_IS_NATIVE
- Make `__attribute__(deprecated)` a no-op
- Fix `__has_include` with framework paths
- Support attributes after identifiers in enums
- Fix dlsym behavior on macOS (RTLD_SELF first, then RTLD_DEFAULT)
- Various tccmacho.c improvements

### Related PRs
- TinyCC fork CI is passing:
https://github.com/oven-sh/tinycc/actions/runs/21105489093

## How did you verify your code works?

- [x] TinyCC fork CI passes on all platforms (Linux
x86_64/arm64/armv7/riscv64, macOS x86_64/arm64, Windows i386/x86_64)
- [ ] Bun CI passes

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Bot <claude-bot@bun.sh>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

cmake/targets/BuildTinyCC.cmake

@@ -4,7 +4,7 @@ register_repository(
   REPOSITORY
     oven-sh/tinycc
   COMMIT
-    29985a3b59898861442fa3b43f663fc1af2591d7
+    12882eee073cfe5c7621bcfadf679e1372d4537b
 )
 
 register_cmake_command(