Non-default weak undefined symbols in executable and shared library are
always resolved to 0 at runtime and don't need dynamic relocation.
Tested on i686, x86-64, powerpc64le and aarch64.
PR gold/32071
* symtab.cc (Symbol::final_value_is_known): Always resolve
non-default weak undefined symbol in executable and shared library
to 0 at runtime.
* symtab.h (Symbol::needs_dynamic_reloc): Return false for
non-default weak undefined symbol in executable and shared library.
* testsuite/Makefile.am: Add weak_undef_test_3 and
weak_undef_test_4 tests.
* testsuite/Makefile.in: Regenerated.
* testsuite/weak_undef_lib_4.c: New file.
* testsuite/weak_undef_test_3.c: Likewise.
* testsuite/weak_undef_test_4.c: Likewise.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>