Properly handle common symbol and weak function

Properly handle common symbol and weak function

bfd/

	PR ld/14591
	* elf-bfd.h (_bfd_elf_merge_symbol): Add an argument to return
	if the old symbol is weak.

	* elf32-sh-symbian.c (sh_symbian_relocate_section): Update
	_bfd_elf_merge_symbol call.

	* elflink.c (_bfd_elf_merge_symbol): Add an argument to return
	if the old symbol is weak.
	(_bfd_elf_add_default_symbol): Update _bfd_elf_merge_symbol
	call.
	(elf_link_add_object_symbols): Don't update symbol type from a
	weak definition.  Update symbol type from a common symbol when
	overriding a weak symbol.

ld/testsuite/

	PR ld/14591
	* ld-elf/comm-data.exp (run_ld_link_tests): Add comm-data3a and
	comm-data3b tests.

	* ld-ifunc/ifunc.exp (run_ld_link_exec_tests): New.

	* ld-elf/comm-data3.sd: New file.
	* ld-elf/comm-data3a.s: Likewise.
	* ld-elf/comm-data3b.s: Likewise.
	* ld-ifunc/ifunc-17a-i386.d: Likewise.
	* ld-ifunc/ifunc-17a-x86-64.d: Likewise.
	* ld-ifunc/ifunc-17a.s: Likewise.
	* ld-ifunc/ifunc-17b-i386.d: Likewise.
	* ld-ifunc/ifunc-17b-x86-64.d: Likewise.
	* ld-ifunc/ifunc-17b.s: Likewise.
	* ld-ifunc/ifunc-common-1.out: Likewise.
	* ld-ifunc/ifunc-common-1a.c: Likewise.
	* ld-ifunc/ifunc-common-1b.c: Likewise.