Squashed 'third-party/libuv/' content from commit 3c40224

git-subtree-dir: third-party/libuv
git-subtree-split: 3c4022464acd92607f21c6eef69330fb071d0400
Merge commit 'a302c65dc65896776d6cb9e2c89a6ccc77ada530' as 'third-party/libuv'
get-libuv.sh: compile bundled libuv

Rename file to reflect new intent of script. Libuv is bundled into the
third-party directory. Modify the script to compile but not fetch libuv.
Makefile: refer to renamed compile-libuv.sh

get-libuv.sh was renamed to compile-libuv.sh
third-party: add note on role of directory

Add a brief README on the purpose of the third-party directory and some
suggestions for how to manage it. The neovim bigwigs may want to
re-draft the README.
Delete local function strerror and USE_GETCWD define.

Both are useless after porting mch_dirname to libuv.
Removes 'proto' dir

See #137 for the issue.

Every header in the proto directory was:

* Given include guards in the form

    #ifndef NEOVIM_FILENAME_H
    #define NEOVIM_FILENAME_H
        ...
    #endif /* NEOVIM_FILENAM_H */

* Renamed from *.pro -> *.h
* Moved from src/proto/ to src/

This would have caused conficts with some existing headers in src/;
rather than merge these conflicts now (which is a whole other can of
worms involving multiple and conditional inclusion), any header in src/
with a conflicting name was renamed from *.h -> *_defs.h (which may or
may not actually describe its purpose, the change is purely a
namespacing issue).

Once all of these changes were made a script was developed to determine
what #includes needed to be added to each source file to describe its
dependencies and allow it to compile; because the script is so short
and I'll just list it here:

    #! /bin/bash

    cd $(dirname $0)

    # Scrapes `make` output for provided error messages and outputs #includes
    # needed to resolve them.
    #   $1 : part of the clang error message between filename and identifier
    list_missing_includes() {
        for file_missing_pair in $(CC=clang make 2>&1 >/dev/null | sed -n "s/\/\(.*\.[hc]\).*$1.*'\(.*\)'.*/\1:\2/p"); do
            fields=(${file_missing_pair//:/ })
            source_file=${fields[0]}
            missing_func=${fields[1]}
            # Try to find the declaration of the missing function.
            echo $(basename $source_file) \
                \#include \"$(grep -r "\b$missing_func __ARGS" | sed -n "s/.*\/\(.*\)\:.*/\1/p")\"
        # Remove duplicates
        done | sort | uniq
    }

    echo "Finding missing function prototypes..."
    list_missing_includes "implicit declaration of function"
    echo "Finding missing identifier declarations..."
    list_missing_includes "use of undeclared identifier"

Each list of required headers was added by hand in the following format:

    #include "vim.h"
    #include "*_defs.h"
    #include "filename.h"
    /* All other includes in same module here, in alphabetical order. */
    /* All includes from other modules (e.g. "os/*.h") here in alphabetical
     * order. */
Merge branch 'bundle-libuv' of github.com:rjw57/neovim into rjw57-bundle-libuv
Remove implicit declaration of vim_strrchr and vim_strncpy