PowerPC64 abort due to dynamic relocs on hidden undefweak
    
    ppc64_elf_relocate_section lacked a check which meant that it emitted
    dynamic relocs against a hidden undefweak symbol for which no dynamic
    relocs had been allocated.
    
    	PR 21224
    	PR 20519
    	* elf64-ppc.c (ppc64_elf_relocate_section): Add missing
    	dyn_relocs check.