rt: regression patch for ARM assembly code

[yichoi]

Regression Path for ARM build failure on #5647

no need to add extra header for ARM assmebly code. already "RW" not "RWX"

readelf -lW arm-linux-androideabi/lib/libcore-c3ca5d77d81b46c1-0.6.so arm-linux-androideabi/lib/librustrt.so arm-linux-androideabi/lib/libstd-4782a756585a81-0.6.so | grep GNU_STACK

GNU_STACK 0x000000 0x00000000 0x00000000 0x00000 0x00000 RW 0
GNU_STACK 0x000000 0x00000000 0x00000000 0x00000 0x00000 RW 0
GNU_STACK 0x000000 0x00000000 0x00000000 0x00000 0x00000 RW 0

[thestinger]

@yichoi: could you switch it to %progbits instead? I didn't realize @ would be invalid on ARM.

I think whether the header is needed depends heavily on the toolchain version.

[thestinger]

Closing in favour of #5655 which fixes the syntax - https://github.com/mirrors/gcc/blob/master/gcc/config/arm/linux-elf.h#L113 seems to indicate that this is needed on at least some ARM platforms/toolchains.

I don't think there's any harm in having it when it's redundant.