Fixed typo.

Author: janpgit

intro.tex

@@ -1748,7 +1748,7 @@
 (\emph{forward declaration}) of functions, variables and macro definitions.
 From the preprocessor's point of view, this is a simple file in the C language.
 \item \emsl{These header files are not specific to UNIX. They are part of
-the ISO~C standard, that is included in POSIX.1 (page \pageref{C_LANGUAGE})
+the ISO~C standard, that is included in POSIX.1 (page \pageref{C_LANGUAGE}).
 It is important to realize that every system that supports ISO~C has to have
 these files, regardless of whether it supports POSIX.1.}
 \item The appropriate header file for given function can be looked up using the