Make `core_maths` optional. #357

	name: Rust

	on: [push, pull_request]

	env:
	CARGO_TERM_COLOR: always

	jobs:
	build:
	runs-on: ubuntu-latest
	strategy:
	matrix:
	rust:
	- 1.51.0
	- stable
	steps:
	- name: Checkout
	uses: actions/checkout@v2

	- name: Install toolchain
	uses: actions-rs/toolchain@v1
	with:
	profile: minimal
	toolchain: ${{ matrix.rust }}
	override: true

	- name: Build with no default features
	run: cargo build --no-default-features --features=no-std-float

	- name: Build with std
	run: cargo build --no-default-features --features=std

	- name: Build with variable-fonts
	run: cargo build --no-default-features --features=variable-fonts,no-std-float

	- name: Build with all features
	run: cargo build --all-features

	- name: Run tests
	run: cargo test

	- name: Build C API
	working-directory: c-api
	run: cargo build --no-default-features

	- name: Build C API with variable-fonts
	working-directory: c-api
	run: cargo build --no-default-features --features=variable-fonts

	- name: Test C API
	working-directory: c-api
	run: \|
	cargo build
	gcc test.c -o test -L./target/debug/ -lttfparser -Werror -fsanitize=address
	env LD_LIBRARY_PATH=./target/debug/ ./test

	- name: Build benches
	working-directory: benches
	run: cargo bench dummy # `cargo build` will not actually build it

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