Stack overflow compiling on macOS

[wirelyre]

Build environment is macOS 10.10.5 (Yosemite).

$ cargo build
   Compiling test_no_warnings v0.0.0 (~/tmp/gl-rs/tests/test_no_warnings)

thread 'main' has overflowed its stack
fatal runtime error: stack overflow
error: Could not compile `test_no_warnings`.

Caused by:
  process didn't exit successfully: `rustc --crate-name test_no_warnings tests/test_no_warnings/lib.rs --color always --crate-type lib --emit=dep-info,link -C debuginfo=2 -C metadata=66f0f0b789771d75 -C extra-filename=-66f0f0b789771d75 --out-dir ~/tmp/gl-rs/target/debug/deps -C incremental=~/tmp/gl-rs/target/debug/incremental -L dependency=~/tmp/gl-rs/target/debug/deps` (signal: 6, SIGABRT: process abort signal)

Discovered via servo/gleam#180.

I'm still working out exactly what's happening. This might be a bug in rustc. It also might have a clean workaround in gl_generator.

[wirelyre]

Some progress in minimizing. The project builds if two particular write_bindings calls are removed from test_no_warnings/build.rs.

However, the build fails if either of those two calls are present, even if all other calls are removed.