I'm installing Pebble SDK by following http://developer.getpebble.com/1/GettingStarted/MacOS/
but when I run
brew doctor and brew install libmpc, it's always saying Error: Cannot write to /usr/local/Cellar.
I thought I have no write permission, and I've run sudo chown -R $USER /usr/local
but it does not work.
How can I install libmpc?
My personal recommendation is to run the Pebble SDK on a Virtual Machine running Ubuntu. I tried getting it installed on Mac OS, and all steps appeared to go as they should, but things were never working right, even after a fair amount of troubleshooting (and I am an experienced Unix/Linux admin). Plus, it did some funny things to some of the custom Unix stuff I had in Mac OS. I installed a VM with Ubuntu and had it up and running quickly and without any complications.
VirtualBox (http://virtualbox.org) is free and works well. You can use Eclipse (and many others) for editing code. And most importantly, you don't run any risk of messing anything up on your Mac OS system while fudging around with the Unix system on your Mac OS install.
Ubuntu is probably the easiest of the *nixes for non-*nix users, so you shouldn't fear the requirement of having to learn how to use Linux. Ubuntu and VirtualBox will take care of most of the difficult stuff for you, and what you can't figure out by virtue of the fact that you are knowledgeable enough about computers to be programming, you will learn from Pebble's instructions and quick Google searches.
There are some additional advantages, such as having your development machine be able to act as the web server from which your test app builds are installed, but you'll figure those out as you go along.