Makefile: Split out a setup target

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

.travis.yml

diff --git a/.travis.yml b/.travis.yml
index b3d54d3..d088936 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -29,11 +29,7 @@
   - popd
 
 install:
-  - rustup target add thumbv7em-none-eabi
-  - rustup target add riscv32imc-unknown-none-elf
-  - rustup component add rustfmt
-  - rustup component add clippy
-  - cargo install elf2tab --version 0.4.0
+  - make setup
   # Build Tock, it needs to be outside of the libtock-rs source
   - pushd ../
   - git clone https://github.com/tock/tock.git

Makefile

diff --git a/Makefile b/Makefile
index 213e36b..53aace9 100644
--- a/Makefile
+++ b/Makefile
@@ -15,9 +15,18 @@
 	@echo " - hifive1"
 	@echo " - nrf52"
 	@echo
+	@echo "Run 'make setup' to setup Rust to build libtock-rs."
 	@echo "Run 'make <board>' to build libtock-rs for that board"
 	@echo "Run 'make test' to test any local changes you have made"
 
+.PHONY: setup
+setup:
+	rustup target add thumbv7em-none-eabi
+	rustup target add riscv32imc-unknown-none-elf
+	rustup component add rustfmt
+	rustup component add clippy
+	cargo install elf2tab --version 0.4.0
+
 .PHONY: examples
 examples:
 	PLATFORM=nrf52 cargo build --release --target=thumbv7em-none-eabi --examples