[RFC] ABI bump for building with gcc4 ?

[Dave Korn]

  Contrary to my earlier reply, I'm now coming round to the opposite point of
view.  If it's a choice of flag day vs. version bumps and an incremental
process, I think the pain will be much less if we choose the latter option.

Charles Wilson wrote:

> 3) -shared-libgcc vs. -static-libgcc.  I was ALSO assuming that
> "recompile with gcc4" was semantically equivalent to "and link with the
> shared libgcc". 

  Important note:  Not by default it isn't, shared libgcc is optional right
now (in plain C only - it's on for all the languages with new runtime DLLs).
It'll be default in the next release.  I probably should have switched it for
this one, but there you go.

> (Side note: Dave, what are your plans for the gcc4 mingw cross compiler?
> sjlj or dw2?  Or maybe just take the mingw.org src tarball and build it
> using "their" cross scripts
>    http://www.mingw.org/wiki/LinuxCrossMinGW
> adapted for our packaging system? etc)

  I'll answer this in a separate thread.

> My plan for libjpeg was to bump the DLL vernum to 100.  And then just
> increment by one as needed. Then *cygwin's* dll number would, in fact,
> be unrelated to the package version, as God and libtool intended.

  This is my overall feeling that makes the version bump OK.  There is no
relationship of necessity between the trailing -NNN suffix on the cygwin DLL
and the upstream ABI version.revision.  Just so long as there's a clear
one-to-one mapping!

    cheers,
      DaveK