fix issue 11293 (locale enumeration for Windows, OS X, Linux, FreeBSD)

Add the missing LC_MESSAGES constant for Linux.

Fix the enumeration values for Windows, OS X and FreeBSD,
which were using Linux's values, incorrectly.
Merge pull request #641 from luismarques/issue_11293

fix issue 11293 (locale enumeration for Windows, OS X, Linux)