Project:Toolchain/Gcc 10 porting notes/fno common

= Overview =

and above flipped a default from to.

This changed code generator to emit globals without explicit initializer from  (via  symbol type) to  (via  symbol type).

= Example =

The problem
will reject multiple definitions of global variables starting from :

The fix (source changes, preferred)
Explicitly mark declarations as such and avoid multiple definitions in order to fix the bug.

The -fcommon workaround (discouraged)
If the problem is not that easy to fix or you are afraid it can break the program you then can report a bug upstream to make the decision on a correct fix.

As a local workaround you can revert back to old behaviour:

= Reproducing the build failure with older gcc versions = The following command can also be used to test your patch

= Links =


 * Upstream ticket: https://gcc.gnu.org/PR85678
 * Tracker
 * This bug is topic of the Bugday 2020-06-06 and Bugday 2020-07-04