Rebuilding RHEL3 libc.so from source

[Michael ODonnell]

>> ...so I suspect that may have something to do with the differences
>> that I mentioned between the libs I'm building versus what's in
>> the RHAT-built RPM.  Can somebody tell me how to persuade rpmbuild
>> to generate anything named *.i686.rpm from that SRPM?
>
> Ah, whoops, forgot about that.  A select few packages get built i686
> as well as i386, with the i686 build being preferred on capable
> systems -- those packages are glibc, openssl and the kernel,
> I believe.  So just:
>
>$ rpmbuild -bb --target i686 glibc.spec
>
>(or rpmbuild --rebuild --target i686 glibc-*.src.rpm)


Wow - what a difference!  Whoops, indeed...

That little tweak resulted in just these 3 RPMs being generated:

   RPMS/i686/glibc-2.3.2-95.50.i686.rpm
   RPMS/i686/glibc-debuginfo-2.3.2-95.50.i686.rpm
   RPMS/i686/nptl-devel-2.3.2-95.50.i686.rpm

...instead of the 10 that were getting built by default, and my
glibc-2.3.2-95.50.i686.rpm now only differs in size from the RHAT-built
one by a few bytes, which are explainable by the presence of my helloWorld
debug stub in there.  It's impressive that (what would seem to be) such
a relatively small change in the target CPU could lead to such wildly
different sizes, contents and number of libraries.

At any rate, this is *much* more like what I wanted - yay!

BTW, that cool dynamic-loader debugging trick I mentioned is this:
invoke any program you like from the command line thus:

   LD_DEBUG=help yourProgramHere

...and the dynamic loader (which is always secretly invoked when you
run anything that uses DSOs - Dynamic Shared Objects) will describe all
the options available to you and then exit without running your program.

Change that "help" to one of the valid options (try "all") and stand back
while the gory details of how the loader resolves every symbol reference
and every library lookup flies by on the screen.  Or that output can be
captured in the location specified by LD_DEBUG_OUTPUT.  Incredibly useful
when your !@$#!! libraries are b0rken.       (guess how I know...)

Thanks again to all for the help.