Linking a static library with -fPIC for flex

[Manoj Srivastava <srivasta@debian.org>]

Hi,

        Starting with version 2.5.31-18 of flex we have started
 providing a static library compiled with position independent code,
 namely, libfl_pic.a, in addition to the normal libfl.a library. This
 is my mail, in accordance to §10.2 of the Debian policy.

        The problem is with packages that contain shared libraries
 with a flex scanner compiled in. Since flex generates code 
 that is not self contained, and the missing symbols live in
 libfl.a. However, since linking a shared library with a object
 containing non position independent code stopped working with gcc 4.1
 (apparently, it was sheer luck that it worked at all). So now we also
 provide libfla_pic.a for shared library packages to link with.

        I was initially going to just provide libfl.a with position
 independent code, which would have prevented the FTBS breakage for
 scanner containing shared libraries, at the expense of a register
 lost for binaries that were otherwise statically linked, and perhaps
 slower execution speeds. When I broached this on IRC, people
 commented that I could provide libfl_pic.a in addition to libfl.a ,
 but compile them both with -fPIC, and transition back at some later
 point to having a non position independent static libfl.a

        Then I realized I was falling into the trap of preferring
 convenience to correctness; the right thing to identify and fix
 packages building shared objects linked to non relocatable code. So,
 now these packages can link to  libfl_pic.a, and binaries can
 continue to link with  libfl.a.

	An alternative would have been to provide a full fledged
 shared library, but that would have been a major break with upstream
 and other distributions that also have flex, and would entail
 creating new library and devel packages for flex, which is more work
 that seems justified (considering that we would have to maintain the
 fork, and keep track of any ABI changes, and all that).

 manoj

arch-tag: 7421b315-d205-4e09-9a81-0fef07ba57b7

-- 
A grammarian's life is always in tense.
Manoj Srivastava   <srivasta@debian.org>  <http://www.debian.org/%7Esrivasta/>
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