message: Add rustcflags to makefile
diff: @@ -2,6 +2,7 @@ TARGET?=
  CARGO?=cargo
  CARGOFLAGS=
  +RUSTCFLAGS=
  BUILD=target
  ifneq ($(TARGET),)
  @@ -72,27 +73,27 @@ test: sysroot
  make -C tests run
  $(BUILD)/debug/libc.a: $(SRC)
  - $(CARGO) build $(CARGOFLAGS)
  + $(CARGO) rustc $(CARGOFLAGS) -- $(RUSTCFLAGS)
  touch $@
  $(BUILD)/debug/crt0.o: $(SRC)
  - CARGO_INCREMENTAL=0 $(CARGO) rustc --manifest-path src/crt0/Cargo.toml $(CARGOFLAGS) -- --emit obj=$@
  + CARGO_INCREMENTAL=0 $(CARGO) rustc --manifest-path src/crt0/Cargo.toml $(CARGOFLAGS) -- --emit obj=$@ $(RUSTCFLAGS)
  touch $@
  $(BUILD)/release/libc.a: $(SRC)
  - $(CARGO) build --release $(CARGOFLAGS)
  + $(CARGO) rustc --release $(CARGOFLAGS) -- $(RUSTCFLAGS)
  touch $@
  $(BUILD)/release/crt0.o: $(SRC)
  - CARGO_INCREMENTAL=0 $(CARGO) rustc --release --manifest-path src/crt0/Cargo.toml $(CARGOFLAGS) -- --emit obj=$@
  + CARGO_INCREMENTAL=0 $(CARGO) rustc --release --manifest-path src/crt0/Cargo.toml $(CARGOFLAGS) -- --emit obj=$@ $(RUSTCFLAGS)
  touch $@
  $(BUILD)/release/crti.o: $(SRC)
  - CARGO_INCREMENTAL=0 $(CARGO) rustc --release --manifest-path src/crti/Cargo.toml $(CARGOFLAGS) -- --emit obj=$@
  + CARGO_INCREMENTAL=0 $(CARGO) rustc --release --manifest-path src/crti/Cargo.toml $(CARGOFLAGS) -- --emit obj=$@ $(RUSTCFLAGS)
  touch $@
  $(BUILD)/release/crtn.o: $(SRC)
  - CARGO_INCREMENTAL=0 $(CARGO) rustc --release --manifest-path src/crtn/Cargo.toml $(CARGOFLAGS) -- --emit obj=$@
  + CARGO_INCREMENTAL=0 $(CARGO) rustc --release --manifest-path src/crtn/Cargo.toml $(CARGOFLAGS) -- --emit obj=$@ $(RUSTCFLAGS)
  touch $@
  $(BUILD)/include: $(SRC)
  