Re: -fpic support in libtool?

[Mike Frysinger]

On Wednesday 02 December 2009 21:27:55 Bob Friesenhahn wrote:
> On Thu, 3 Dec 2009, Joakim Tjernlund wrote:
> > Several years ago I asked libtool to support -fpic too but
> > I don't see it in never libtool(s). I guess it isn't
> > impl.?
> >
> > The simplest fix for adding -fpic I can come up with is
> > doing sed -i 's/-fPIC/-fpic/' aclocal.m4
> > This is a bit clumsy as one can easily forget
> > to do this when running aclocal manually.
> > Is there a simpler way? One that will work both with 1.5 and 2.x
> > versions of libtool?
> 
> How would libtool know which PIC variant will work?  Note that some
> targets (e.g. PowerPC & SPARC) offer many reduced PIC variants.
> These don't really work unless the developer is able to validate the
> application/library on many kinds of targets and somehow specify the
> correct variant which works for the target.
> 
> Libtool can be influenced by the configure script by influencing this
> definition which gets output in the libtool script:
> 
> # Additional compiler flags for building library objects.
> pic_flag=" -fPIC -DPIC"
> 
> This seems to be controlled by the lt_prog_compiler_pic configure
> script variable.
> 
> Note that many compilers use something quite different from -fPIC to
> mean the same thing but don't accept -fpic so just
> substituting/inserting -fpic is likely to cause failure.

it isnt just a target-specific issue.  it's package specific too.  for smaller 
libraries, people can get away with -fpic.  but you really have no way of 
knowing until you try and compile something and it fails due to exceeding the 
smaller space.
-mike

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