Fix typos
Fix typos of open() flag

O_SEQENTIAL -> O_SEQUENTIAL
readdir() may crash when FindFirstFileEx() fails
Merge pull request #113 from k-takata/topic/fix-readdir-win32

readdir() may crash when FindFirstFileEx() fails
Merge pull request #112 from k-takata/topic/fix-typo-of-flag

Fix typos of open() flag
Merge pull request #111 from k-takata/topic/fix-typo-in-readme

Fix typos
Improve check windows
Improve expand()
Fix #114 remove GPL code in proc_w32.c and change the license to MIT.
Proper copyright notice
Merge pull request #117 from ichizok/copyright

Proper copyright notice
More explicitly specified gcc exec

If used on a system with Cygwin installed, the old makefile using just `gcc` would fail. More explicitly specifying the mingw compiler ensures that this will work properly.
Merge pull request #119 from natemara/master

More explicitly specified gcc exec
avoid using gcc or mingw32-gcc directly, use CC instead

When MinGW(-w64) package is installed on Cygwin, the executable name is
i686-pc-mingw32-gcc, i686-w64-mingw32-gcc or x86_64-w64-mingw32-gcc.
It's better to define CC variable and use it.

Related: #119
Merge pull request #120 from k-takata/avoid-using-gcc-directly

avoid using gcc or mingw32-gcc directly, use CC instead
Improve documentation
Fix MinGW64 build issue (fix #123, #122)

MinGW64 doesn't have mingw32-gcc. $(CC) should be x86_64-w64-mingw32-gcc.
update internal command list
internal commands should be searched with ignore case mode
Merge pull request #125 from k-takata/fix-windows-internal-commands

Fix windows internal commands