Auto merge of #148992 - Zalathar:rollup-c1aqvox, r=Zalathar

Rollup of 3 pull requests

Successful merges:

 - rust-lang/rust#145954 (stabilize extern_system_varargs)
 - rust-lang/rust#148962 (fix(span): track unnormalized source len for dep-info)
 - rust-lang/rust#148969 (compiletest: Don't apply "emscripten" directives to `wasm32-unknown-unknown`)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

src/tests/directives.md

@@ -141,8 +141,7 @@ Some examples of `X` in `ignore-X` or `only-X`:
 - OS: `android`, `emscripten`, `freebsd`, `ios`, `linux`, `macos`, `windows`,
   ...
 - Environment (fourth word of the target triple): `gnu`, `msvc`, `musl`
-- WASM: `wasm32-bare` matches `wasm32-unknown-unknown`. `emscripten` also
-  matches that target as well as the emscripten targets.
+- WASM: `wasm32-bare` matches `wasm32-unknown-unknown`.
 - Pointer width: `32bit`, `64bit`
 - Endianness: `endian-big`
 - Stage: `stage1`, `stage2`