Patch for PR middle-end/10109 - Fix LIBCALL_VALUE documentation

[<sje at cup dot hp dot com>]

This patch is my attempt to fix PR middle-end/10109, a bug report about
the documentation of the LIBCALL_VALUE macro in tm.texi.

I changed the use of LIBRARY_VALUE to LIBCALL_VALUE since that seems
to be what it was intended.

I removed the comment about not worrying about aggregate types since the
macro doesn't take a 'type' it only takes a mode.  I suppose we could
say something about not worrying about BLKmode but it seems irrelevent to
do so.

I also removed the comments about the 'func' argument since that no
longer exists.  I think LIBCALL_VALUE (or LIBRARY_VALUE) used to take
more arguments but it currently only takes a single argument, a mode.

2009-02-23  Steve Ellcey  <sje@cup.hp.com>

	PR middle-end/10109
	* tm.texi (LIBCALL_VALUE): Update description.


Index: tm.texi
===================================================================
--- tm.texi	(revision 144379)
+++ tm.texi	(working copy)
@@ -4304,20 +4304,12 @@ a new target instead.
 
 @defmac LIBCALL_VALUE (@var{mode})
 A C expression to create an RTX representing the place where a library
-function returns a value of mode @var{mode}.  If the precise function
-being called is known, @var{func} is a tree node
-(@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null
-pointer.  This makes it possible to use a different value-returning
-convention for specific functions when all their calls are
-known.
+function returns a value of mode @var{mode}.
 
 Note that ``library function'' in this context means a compiler
 support routine, used to perform arithmetic, whose name is known
 specially by the compiler and was not mentioned in the C code being
 compiled.
-
-The definition of @code{LIBRARY_VALUE} need not be concerned aggregate
-data types, because none of the library functions returns such types.
 @end defmac
 
 @defmac FUNCTION_VALUE_REGNO_P (@var{regno})