Consistently use \POSIX{} to denote POSIX.  There were at least two different
ways to do it previously (not counting module names).
diff --git a/Doc/liblocale.tex b/Doc/liblocale.tex
index 602988b..a0ecf39 100644
--- a/Doc/liblocale.tex
+++ b/Doc/liblocale.tex
@@ -3,9 +3,9 @@
 
 \label{module-locale}
 
-The \code{locale} module opens access to the POSIX locale database and
-functionality. The POSIX locale mechanism allows applications to
-integrate certain cultural aspects into an applications, without
+The \code{locale} module opens access to the \POSIX{} locale database
+and functionality. The \POSIX{} locale mechanism allows applications
+to integrate certain cultural aspects into an applications, without
 requiring the programmer to know all the specifics of each country
 where the software is executed.