This change adds an `--enable-simd` flag to the binaries in this project. This allows the ISA `enable_simd` flag to be set and to configure the validation configuration used by wasmparser to allow SIMD instructions.
* Simple module compilation cache
* Fix base64 encoding bug
* Use warn! everywhere in cache system
* Remove unused import
* Temporary workaround for long path on Windows
* Remove unused import for non-windows builds
* Add command line argument to enable cache system + apply minor review feedback
Even though this somehow passed on Travis on [the
PR](https://github.com/CraneStation/wasmtime/pull/209), it fails on
Travis on master, and I can reproduce the failure.
The failure is on spec_testsuite/names.wast:
```
$ RUST_BACKTRACE=1 target/debug/wast spec_testsuite/names.wast
thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: FromUtf8Error { bytes: [255], error: Utf8Error { valid_up_to: 0, error_len: Some(1) } }', src/libcore/result.rs:999:5
stack backtrace:
[...]
9: core::result::Result<T,E>::unwrap
at /rustc/a53f9df32fbb0b5f4382caaad8f1a46f36ea887c/src/libcore/result.rs:800
10: wabt::script::jstring_to_rstring
at [...]/.cargo/registry/src/github.com-1ecc6299db9ec823/wabt-0.8.0/src/script/mod.rs:261
11: wabt::script::parse_action
at [...]/.cargo/registry/src/github.com-1ecc6299db9ec823/wabt-0.8.0/src/script/mod.rs:274
12: wabt::script::ScriptParser<F32,F64>::next
at [...]/.cargo/registry/src/github.com-1ecc6299db9ec823/wabt-0.8.0/src/script/mod.rs:504
13: wasmtime_wast::wast::WastContext::run_buffer
at wasmtime-wast/src/wast.rs:202
14: wasmtime_wast::wast::WastContext::run_file
at wasmtime-wast/src/wast.rs:472
15: wast::main
at src/wast.rs:107
[...]
```
