alan_2: add -fcommon workaround for gcc-10
alan_2: add -fcommon workaround for gcc-10

Without the change the build against upstream gcc-10 build fails as:

    ld: smScSema.o:/build/source/compiler/smScSema.c:135:
        multiple definition of `charset'; options.o:/build/source/compiler/options.c:16: first defined here

Use -fcommon as a workeround until upstream updates the code.

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