Added -fcommon to compile option in order to make multiple definition warnings instead of errors

Since GCC 10, the new default is -fno-common, so it breaks compilation because of now unsupported "ld: multiple definition". This MR makes it compile again by forcing -fcommon to the compile chain.

(reference: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85678)

assigned to @ranini2019

unassigned @ranini2019

approved this merge request

enabled an automatic merge when the pipeline for 702a7afb succeeds

canceled the automatic merge

merged