Hyphenate "built-in" for consistency.

Doc/ext.tex

@@ -134,7 +134,7 @@ passed to the \C{} function.  The \C{} function always has two arguments,
 conventionally named \var{self} and \var{args}.
 
 The \var{self} argument is only used when the \C{} function implements a
-builtin method.  This will be discussed later. In the example,
+built-in method.  This will be discussed later. In the example,
 \var{self} will always be a \NULL{} pointer, since we are defining
 a function, not a method.  (This is done so that the interpreter
 doesn't have to understand two different types of \C{} functions.)

Doc/ext/ext.tex

@@ -134,7 +134,7 @@ passed to the \C{} function.  The \C{} function always has two arguments,
 conventionally named \var{self} and \var{args}.
 
 The \var{self} argument is only used when the \C{} function implements a
-builtin method.  This will be discussed later. In the example,
+built-in method.  This will be discussed later. In the example,
 \var{self} will always be a \NULL{} pointer, since we are defining
 a function, not a method.  (This is done so that the interpreter
 doesn't have to understand two different types of \C{} functions.)

Doc/lib/liblocale.tex

@@ -102,7 +102,7 @@ collates before or after \var{string2} or is equal to it.
 \end{funcdesc}
 
 \begin{funcdesc}{strxfrm}{string}
-Transforms a string to one that can be used for the builtin function
+Transforms a string to one that can be used for the built-in function
 \function{cmp()}\bifuncindex{cmp}, and still returns locale-aware
 results.  This function can be used when the same string is compared
 repeatedly, e.g. when collating a sequence of strings.

Doc/liblocale.tex

@@ -102,7 +102,7 @@ collates before or after \var{string2} or is equal to it.
 \end{funcdesc}
 
 \begin{funcdesc}{strxfrm}{string}
-Transforms a string to one that can be used for the builtin function
+Transforms a string to one that can be used for the built-in function
 \function{cmp()}\bifuncindex{cmp}, and still returns locale-aware
 results.  This function can be used when the same string is compared
 repeatedly, e.g. when collating a sequence of strings.