Fixed GCC version test.

[Remotion]

Please see here for more info #770

[vitaut]

Thanks for the PR. One comment and please rebase since quotation functionality has already been merged.

[vitaut]

I think you could use FMT_GCC_VERSION instead of __GNUC__ * 100 + __GNUC_MINOR__ (possibly after reordering defines).

[eliaskosunen]

FMT_GCC_VERSION is defined in core.h, which is included after this. This also needs to be before the inclusion of core.h to disable warnings from that header. On your first review in #736 you said that FMT_GCC_VERSION needs to be in core.h.

So that leaves two options that I can think of:

1. Leave it as is
2. Duplicate these warning-disabling maneuvers in both core.h and format.h and move the inclusion of core.h before the disabling of the warnings in format.h, so both can use FMT_GCC_VERSION, like this:

// core.h
#define FMT_GCC_VERSION /* ... */

#if FMT_GCC_VERSION
// disable
#endif

// ...

#if FMT_GCC_VERSION
// re-enable
#endif

// format.h

#include "core.h"

#if FMT_GCC_VERSION
// disable
#endif

// ...

#if FMT_GCC_VERSION
// re-enable
#endif

[eliaskosunen]

I said that very incoherently. What I was trying to say was that the warnings need to be disabled before the inclusion of core.h, but FMT_GCC_VERSION is defined in core.h. So we can either not use FMT_GCC_VERSION in disabling the warnings or disable them in both headers. The latter would probably be preferable, because now the warnings aren't disabled at all if you only include core.h.

[vitaut]

I think we can live without disabling these warnings in fmt/core.h for now, so I suggest just moving fmt/core.h to the front and using FMT_GCC_VERSION here.

[eliaskosunen]

The original point of this PR was to fix the version check so there wouldn't be any -Wshadow warnings.

[vitaut]

Yes and this will fix the reported warnings in fmt/format.h (but not in fmt/core.h which is OK since no such warnings were reported).