This adds a toehold integration for emscripten users, so they don't
have to define the memory growth function.
Fixes#601
Signed-off-by: Adrian Cole <adrian@tetrate.io>
We get undefined behavior, at least in code that re-slices, unless
capacity is set. This ensures the buffer under the string has a capacity
set to the same length as its size. This also shows more explicitly the
problems in TinyGo (ex some type mismatch you have to ignore until
fixed).
Signed-off-by: Adrian Cole <adrian@tetrate.io>
