Bump ext/SDL from a2c1984 to 49d58bc

Bumps [ext/SDL](https://github.com/libsdl-org/SDL) from `a2c1984` to `49d58bc`.
- [Release notes](https://github.com/libsdl-org/SDL/releases)
- [Commits](libsdl-org/SDL@a2c1984...49d58bc)

---
updated-dependencies:
- dependency-name: ext/SDL
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>