Make flate2/zlib feature optional to enable compiling to WASM.

[ajrcarey]

Thank you for such a useful crate! As currently implemented, the use of the flate2/zlib feature in Cargo.toml prevents compiling to WASM, since zlib is not available. Would it be possible to make this dependency optional? Something like the following would do it:

[package]
name = "allsorts"
version = "0.6.0"
authors = ["YesLogic Pty. Ltd. <[email protected]>"]
edition = "2018"

homepage = "https://github.com/yeslogic/allsorts"
documentation = "https://docs.rs/crate/allsorts"
repository = "https://github.com/yeslogic/allsorts"

readme = "README.md"
license = "Apache-2.0"
include = ["/LICENSE", "src/**/*"]

description = "Font parser, shaping engine, and subsetter for OpenType, WOFF, and WOFF2"
keywords = ["font", "shaping", "opentype", "truetype", "parse"]
categories = ["text-processing"]

[dependencies]
bitflags = "1.0"
bitreader = "0.3.2"
brotli-decompressor = "2.3"
byteorder = "1.2"
encoding_rs = "0.8.16"
flate2 = { version = "1.0", default-features = false }
glyph-names = "0.1"
itertools = "0.8"
lazy_static = "1.3.0"
libc = "0.2"
log = "0.4"
num-traits = "0.2"
ouroboros = "0.9"
rustc-hash = "1.1.0"
tinyvec = { version = "1", features = ["alloc"] }
ucd-trie = "0.1.2"
unicode-canonical-combining-class = "0.1.0"
unicode-general-category = "0.3"
unicode-joining-type = "0.4.0"

# Optional dependencies
pathfinder_geometry = { version = "0.5.1", optional = true }

[dev-dependencies]
regex = "1.1.6"

# criterion = "0.3"

# [[bench]]
# name = "bench-shape"
# harness = false

# [[bench]]
# name = "bench-read"
# harness = false

[features]
default = ["outline", "zlib"]
prince = []
outline = ["pathfinder_geometry"]
zlib = ["flate2/zlib"]
miniz_oxide = ["flate2/default"]

The flate2/zlib feature is now exposed by allsorts/zlib, which is added to the default features. So by default everything remains exactly the same. But now consumers who want to compile to WASM (or other scenarios where zlib is not available) can remove that feature and use the allsorts/miniz_oxide feature instead.

No doubt there's other, possibly more elegant, ways of doing this, but this seems a simple enough solution.

Possibly related to #7.

[wezm]

That seems reasonable. Most of the YesLogic folks are on leave at the moment. We should be able to add this in the new year. I return 11 Jan, feel free to ping me at the end of that week if you haven't heard anything by then.

[wezm]

I've pushed a change to implement this. I hope to make a release this week but we've got a few other tweaks in the works that I'd like to include so will hold off for a day or so.

[ajrcarey]

Many thanks, I look forward to the next release.

[wezm]

New release has been published.