Fix linkage of global identifiers

[ghost]

Align the code to the standard and modern compilers.

Signed-off-by: Andreas Kölbl koelblandreas@freenet.de

[dfandrich]

Looks like an alternate take on PR#13.

[ecashin]

Can you please update the documentation with information about what version of gcc introduced this option and how to build differently when using an older gcc?
Sorry I am not responsive lately, but I'll try to keep an eye out for your response.

[ghost]

I don't know how this is information is valuable to someone reading the doc. The old code would still compile when using -fcommon as flag.

[ecashin]

When was that option first sorted in gcc? If it was long enough ago, and there's no disadvantage to using it, then you're right.
The documentation will help people understand why we use the option if they're using an old gcc or trying to use their own favorite compiler instead of gcc.

[ghost]

You are right, we should leave the compile flag out in order to avoid confusion and enhance cross-compiler-portability as -fno-common serves ANSI-C-like behaviour. I don't think the flag has more functionality behind than to make its own usage obvious. The oldest reference I found was an 18 year old Changelog entry to compile gcc itself with that flag.

[ecashin]

18 years is long enough!