Fails to compile with `-fno-common` / GCC 10

[candrews]

Version 3.5.0 https://github.com/RadeonOpenCompute/ROCm-OpenCL-Runtime/tree/roc-3.5.0 fails to compile with -fno-common, which is default with GCC 10.

In summary, this will not compile with GCC 10. For more information, please see https://wiki.gentoo.org/wiki/Gcc_10_porting_notes/fno_common

[vsytch]

You can see the supported distros here: https://github.com/RadeonOpenCompute/ROCm#supported-operating-systems

Technically non of those utilize gcc10, so we never tested that path, but it doesn't hurt to fix this.