Say 'specifying' instead of 'which specifies' after em-dash

chapters/functions.tex

@@ -1725,11 +1725,8 @@ \section{External Function Interface}\doublelabel{external-function-interface}
 This is just as for any other function.  The components in the protected part allow local variables for temporary storage to be declared.
 \end{nonnormative}
 
-The \lstinline!language-specification! must currently be one of \lstinline!"builtin"!,
-\lstinline!"C"!, \lstinline!"C..."! (for one of the specific C-standards like C89, C99, and C11
--- which specifies that it relies on the C standard library of that
-version) or \lstinline!"FORTRAN 77"!. Unless the external language is specified, it
-is assumed to be \lstinline!"C"!.
+The \lstinline!language-specification! must currently be one of \lstinline!"builtin"!, \lstinline!"C"!, \lstinline!"C..."! (for one of the specific C-standards like C89, C99, and C11 --- specifying
+that it relies on the C standard library of that version) or \lstinline!"FORTRAN 77"!.  Unless the external language is specified, it is assumed to be \lstinline!"C"!.
 
 \begin{nonnormative}
 The intended use of e.g.\ C99 is to detect if the user tries to link with a C99-function using a C89 compiler.