libc_hidden_proto breaks things for PowerPC64

["Steve Munroe" <sjmunroe at us dot ibm dot com>]

The use of the libc_hidden_proto macro when combined with the weak_alias
macro results in  unresolved references in libc.so. For example.

   /work/usr/src/build-23/libc.so.6: undefined reference to `.__sysconf'
   /work/usr/src/build-23/libc.so.6: undefined reference to `.__iswpunct_l'
   /work/usr/src/build-23/libc.so.6: undefined reference to `.__gmtime_r'
   /work/usr/src/build-23/libc.so.6: undefined reference to `.__iswgraph_l'
   /work/usr/src/build-23/libc.so.6: undefined reference to `.
   ____strtoul_l_internal'
   ...

The problem seems to be the combination of libc_hidden_proto and weak_alias
macros. For example ./sysdeps/posix/sysconf.c is externally defined by:

    libc_hidden_proto(__sysconf)

which generates the following:

   extern long int __sysconf (int __name);
   extern __typeof (__sysconf) __GI___sysconf; extern __typeof (__sysconf)
   __sysconf __asm__ ("" "__GI___sysconf") ;

When  ./sysdeps/posix/sysconf.c is compiled, this causes the symbol "
__sysconf" to be replaced for symbol "__GI___sysconf" in the function
prolog:

    .globl __GI___sysconf
    .section ".opd","aw"
    .align 3
   __GI___sysconf:
    .quad .__GI___sysconf,.TOC.@tocbase,0
    .previous
    .size __GI___sysconf,24
    .type .__GI___sysconf,@function
    .globl .__GI___sysconf
   .__GI___sysconf:

But the weak_alias statement at the end of ./sysdeps/posix/sysconf.c

   weak_alias(__sysconf, sysconf)

generates:

   extern __typeof (__sysconf) sysconf __attribute__ ((weak, alias ("
   __sysconf")));

which generates the following asm:

    .weak sysconf
    .weak .sysconf
    .set .sysconf,.__sysconf
    .set sysconf,__sysconf

The result is a reference to the symbol ".__sysconf" which is not defined
(because it was replaced with "__GI___sysconf".  This problem is showing up
on PowerPC64 because of the "DOT_SYMBOLS" but there may be a hidden problem
on other architectures. The reference to symbol  "__sysconf" does not seem
to cause a problem because the "opd" entry is generated implicitly, but it
can't be resolved.

It is not clear to me how ths should be resolved.

Does the weak_alias macro need to be updated to work with
libc_hidden_proto?
Do we need a libc_hidden_weak_alias macro?
If this function is hidden, should the weak_alias be used at all?
Is there a compiler/binutils issue here?

I am building for PowerPC64

cpu:        Power3 (630+)
machine:    IBM 7044-170
Kernel:           2.4.19-rc3
GCC:         3.2 20020729 (prerelease)
binutils:         2.13.90
glibc:            from cvs pulled 08/08/2002