rustup fails to install gcc on some windows platforms

[Robbepop]

Recently I started to receive appveyor build errors for all of my projects with the following error message:

error: aborting due to previous error(s)
error: Could not compile `smt-expr-derive`.
Caused by:
  process didn't exit successfully: `rustc --crate-name smt_expr_derive smt-expr-derive\src\lib.rs --crate-type proc-macro --emit=dep-info,link -C prefer-dynamic -C debuginfo=2 -C metadata=6feb16d7e2a8e571 -C extra-filename=-6feb16d7e2a8e571 --out-dir C:\projects\stevia\target\debug\deps -L dependency=C:\projects\stevia\target\debug\deps --extern syn=C:\projects\stevia\target\debug\deps\libsyn-e662069961d8f963.rlib --extern quote=C:\projects\stevia\target\debug\deps\libquote-983cfcbeae6039c8.rlib` (exit code: 101)

Appveyor Link

As far as I know rustup is supposed to install gcc on windows but on some windows platforms it no longer does and thus breaks all my appveyor builds. Other platforms, like linux, are not affected as far as I can tell.

I was forwarded to rustup through IRC channel #rust and hope that this is the right place for this issue.

[mati865]

The issue is rust-lang/rust#42422
Nightly is fixed already.