This bumps the highest valid EI_ABIVERSION value to ABSOLUTE ABI.
New testcase loads the symbol from the GOT with the "lb" instruction
so that the EI_ABIVERSION header field of the shared object is set
to ABSOLUTE (it doesn't actually check the value of the symbol), and
makes sure that the main executable is executed without "ABI version
invalid" error.
Tested for all three ABIs (o32, n32, n64) using both static linker which
handles undefined weak symbols correctly [1] (and sets the EI_ABIVERSION
of the test module) and the one that doesn't (EI_ABIVERSION left as 0).
[1] https://sourceware.org/ml/binutils/2018-07/msg00268.html
[BZ #24916]
* sysdeps/mips/Makefile [$(subdir) = elf] (tests): Add
tst-undefined-weak.
[$(subdir) = elf] (modules-names): Add tst-undefined-weak-lib.
[$(subdir) = elf] ($(objpfx)tst-undefined-weak): Add dependency.
* sysdeps/mips/tst-undefined-weak-lib.S: New file.
* sysdeps/mips/tst-undefined-weak.c: Likewise.
* sysdeps/unix/sysv/linux/mips/ldsodefs.h (VALID_ELF_ABIVERSION):
Increment highest valid ABIVERSION value.
