Re: -no-undefined (was: libposix)

[Bruno Haible]

Hi Ralf,

> even *if* gnulib lists all
> required libraries correctly and the developer uses them correctly,
> then using the -Wl,-z,defs link flag could cause spurious link failures
> on GNU/Linux because of games played with symbol definitions in one of
> glibc, GCC, or binutils (I don't remember).  This has prevented libtool
> from providing an effective way to fail due to symbols undefined in
> shared libraries.

Understood. But even if libtool had this feature, its usefulness would be
limited in the scope of gnulib: You could not assert that a program's or
library's _LDFLAGS variable is complete, just by testing on Linux. Some of
the variables (LIB_EACCESS, LTLIBICONV, GETHOSTNAME_LIB, LIBTHREAD, etc.)
are empty on Linux. Therefore when a programmer made the mistake to forget
such a variable on the link line, the only situation where a link can fail
is on a system where this variable is set to non-empty.

Bruno