Version 1.0.26

Version 1.0.25 (WebAssembly#1788)

Version 1.0.24 (WebAssembly#1701)

Version 1.0.23 (WebAssembly#1654)

- add _free to exports for building libwabtjs

Version 1.0.22 (WebAssembly#1650)

- thirdparty/testsuite updates
- WASI compilation fixes
- 32-bit compile fixes
- SIMD updates

Version 1.0.21 (WebAssembly#1618)

Rename atomic.notify, *.atomic.wait (WebAssembly#1564)

atomic.notify   -> memory.atomic.notify
i32.atomic.wait -> memory.atomic.wait32
i64.atomic.wait -> memory.atomic.wait64

These were renamed upstream a while ago, but the new names were not
added to wabt.

Completely disable signal handler on 32-bit (WebAssembly#1488)

The previous change prevented `WASM_RT_MEMCHECK_SIGNAL_HANDLER_POSIX`
from being defined, but `WASM_RT_MEMCHECK_SIGNAL_HANDLER` was still
defined, which would prevent the memory bounds check.

Use #warning instead of #warn (WebAssembly#1487)

Add install prefix for build releases [skip ci]