In order to maintain consistency both within machine/arm and between
machine/arm and machine/aarch64, rename the 'c' stub to -stub.c.
Tested by building newlib and comparing libc.a binaries before and
after for all permutations of:
Architectures:
armv4 armv4t armv5 armv5t armv5te armv6 armv6j armv6k
armv6z armv6kz armv6t2 armv6-m armv6s-m armv7 armv7-a
armv7ve armv7-r armv7-m armv7e-m armv8-a iwmmxt iwmmxt2
ISAs:
thumb arm
Optimization Levels:
Os O2
Excluding:
armv6s-m -mthumb
armv6-m -mthumb
armv6zk -mthumb
armv6z -mthumb
armv6k -mthumb
armv6j -mthumb
Marcus Shawcroft