[MacPorts] #49821: libsndfile - update to 1.0.26

[Jan Stary]

> On Nov 26 20:20:28, noreply at macports.org wrote:
> > #49821: libsndfile - update to 1.0.26
> > -------------------------+--------------------------------
> >   Reporter:  hans@???      |      Owner:  macports-tickets@???
> >       Type:  update      |     Status:  new
> >   Priority:  Normal      |  Milestone:
> >  Component:  ports       |    Version:  2.3.4
> > Resolution:              |   Keywords:  haspatch
> >       Port:  libsndfile  |
> > -------------------------+--------------------------------
> > 
> > Old description:
> > 
> > > Here is a patch to the Portfile of audio/libsndfile
> > > which brings it to the latest 1.0.26 release,
> > > and the upgraded version of files/
> > >
> > > The speex.patch removes SPEEX_* from EXTERNAL_* in configure;
> > > I believe speex.patch is a better name, and configure.patch
> > > should be replaced with this.
> > >
> > > The carbon.patch is a better version of fix-include.patch
> > > which it should replace. Not only does it remove the Carbon.h include
> > > from sndfile-play.c, but it removes Carbon altogether.
> > >
> > > I am leaving src__config.h.ed as is, but I am not completely sure
> > > about its purpose; if __BIG_ENDIAN__, __LP64__, etc, is defined,
> > > then ./configure (which creates config.h) is supposed to figure out
> > > the SIZEOF_LONG etc, right? If not, it's a bug in configure,
> > > not something we should patch in the resulting config.h, right?
> > >
> > > I also removed the sqlite variant from the Portfile.
> > > Only sndfile-regtest uses sqlite; does anybody use sndfile-regtest?
> > >
> > > Jan
> > 
> >  You can easily discover using "svn log" and "svn blame" that this file was
> >  added in r42762 to resolve #17088, when libsndfile was at version 1.0.17.
> 
Thanks for the pointer, I have my svn tree now.

The root cause seems to be
http://www.mega-nerd.com/libsndfile/FAQ.html#Q018
Please help me understand it clearly (author cc'd).
The chunks of the diff between the original config.h
and the patched one look like this:

 	+#ifdef __LP64__
 	+#define CPU_CLIPS_NEGATIVE 0
 	+#else
  	#define CPU_CLIPS_NEGATIVE 1
 	+#endif
  	
 	+#ifdef __BIG_ENDIAN__
 	+#define CPU_IS_BIG_ENDIAN 1
 	+#else
  	#define CPU_IS_BIG_ENDIAN 0
 	+#endif

Why do we need this?
The defines are used in code like this:
 
   if (CPU_CLIPS_POSITIVE == 0 && scaled_value >= (1.0 * 0x7FFFFFFF)) {
 	  dest [count] = 127 ;
 	  continue ;
   } ;
 
 
The condition (CPU_CLIPS_POSITIVE == 0) is decided at compile time,
whether it is defined to be 0 or 1. So even with the patch,
libsndfile is compiled to behave this way, or it is compiled
to behave the other way.
 
I don't have a BIGENDIAN mac or a LP64 mac to test on,
but doesn't ./configure just define the constants
to be the appropriate value, on a LP64 machine?
Can people with BIGENDIAN or LP64 machine please test?

Maybe I am missing something obvious, but how exactly does this
patch result in a universal binary, as opposed to without it?
 
 	Jan