[patch] Include some c99 functions in __STRICT_ANSI__ for cygwin c99.

[Dave Korn <dave dot korn dot cygwin at googlemail dot com>]

    Hello Jeff and list,

Refs: http://www.cygwin.com/ml/cygwin/2009-04/threads.html#00435
      http://cygwin.com/ml/cygwin/2009-10/threads.html#00324
      http://cygwin.com/ml/cygwin/2009-10/msg00406.html

  We had a couple of complaints over on the Cygwin list about function
prototypes not present when using --std=c99; this is of course to be expected
since newlib's definition of _STRICT_ANSI_ is based as we all know on c90, and
none of those functions were defined in the earlier ANSI standards.

  On Cygwin, we'd like to be as Linux, POSIX and c99 compatible as we can,
which is why this patch only changes the semantics of _STRICT_ANSI_ when
__CYGWIN__.  If the c99 standard is in effect, then it includes all the
functions that people have complained about missing: the {sn,v*}{print,scan}f
family and f{seek,tell}o.

  I've made this conditional on __CYGWIN__ so as not to produce any unexpected
side-effects for any other users, but you might decide it makes as much sense
to make this an unconditional change.

  However, even in that case, a Cygwin-specific bit may be needed:

  The new formatted i/o functions are part of c99, but the fseeko and ftello
functions are not; they are only part of POSIX.  Since Linux/Glibc includes
their declarations in _STRICT_ANSI_ (taking, if I've read the wording right,
advantage of the leeway provided by the definition of the CX extension type
annotation in the SUS to allow them to be regarded as extensions to the c99
spec in this context, as described in the third reference above), and since
Cygwin's goal is Linux emulation, it certainly makes sense to include them in
_STRICT_ANSI_ for Cygwin.

  Other platforms might only want the formatted i/o functions from the core
c99 spec to be added to _STRICT_ANSI_, depending on their own stance toward
POSIX compliance.  So even if it was desirable to make this change not
conditional on __CYGWIN__, I think it might still make sense to keep this part
of the change Cygwin-only.  Then again, there are also Linux newlib platforms;
they'd probably like to have the definitions visible in c99 mode.

  So, here's the patch, and I figured I'd leave it to you to decide what's the
best form for the conditional to take.  Tested by building a winsup checkout
before and after the change in separate objdirs, installing both into separate
DESTDIRs, manually verifying the difference was in the second installed header
and not the first, and that the warnings from the testcases posted to the
threads referenced above were manifested when compiling with a -I option into
the before DESTDIR/usr/include and not generated when compiling with a -I
option pointing into the after DESTDIR/usr/include.

newlib/ChangeLog:

	* libc/include/stdio.h: Include additional C99 formatted I/O
	functions and POSIX fseeko/ftello in _STRICT_ANSI_ for Cygwin
	when __STDC_VERSION__ indicates C99 or later standard in use.

  What do you think?

    cheers,
      DaveK


Index: newlib/libc/include/stdio.h
===================================================================
RCS file: /cvs/src/src/newlib/libc/include/stdio.h,v
retrieving revision 1.58
diff -p -u -r1.58 stdio.h
--- newlib/libc/include/stdio.h	3 Jul 2009 11:58:04 -0000	1.58
+++ newlib/libc/include/stdio.h	14 Oct 2009 06:33:14 -0000
@@ -232,7 +232,7 @@ int	_EXFUN(sprintf, (char *, const char 
 int	_EXFUN(remove, (const char *));
 int	_EXFUN(rename, (const char *, const char *));
 #endif
-#ifndef __STRICT_ANSI__
+#if !defined (__STRICT_ANSI__) || (defined (__CYGWIN__) &&  __STDC_VERSION__ >= 199901L)
 #ifdef _COMPILING_NEWLIB
 int	_EXFUN(fseeko, (FILE *, _off_t, int));
 _off_t	_EXFUN(ftello, ( FILE *));