cscope/emacs: example Linux setup

This is a simple recipe for being setting up jump-to-file (for #includes) and jump-to-declaration (for symbol names) in emacs, on gprecise (should work on most posix systems).

• Install cscope: sudo apt-get install -y cscope cscope-el
• Place the attached cscope-update script in the directory containing .gclient (parent of src/).
• Run ./cscope-update after each gclient sync to update the cscope database
• Load the attached cscope.el from your .emacs; note you'll probably want to edit this with your own client roots in ami-src-root-for-buffer.
• While browsing source, hit meta-. (period) to jump to the file #included at point or to the declaration of the symbol at point.