bfd * elf32-arm.c (elf32_arm_fix_exidx_coverage): Insert cantunwind when
address in first unwind entry does not match start of section.
tests * ld-arm/arm-elf.exp: New test.
* ld-arm/unwind-mix.d: New file.
* ld-arm/unwind-mix1.s: New file.
* ld-arm/unwind-mix2.s: New file.