Fix an error reported by gcc about format-security

[bcoconni]

On Fedora 32, gcc 10.2.1 reports an error:

 Compiling file src/SDL/MyOpenGLView.m ...
src/SDL/MyOpenGLView.m: In function ‘-[MyOpenGLView init]’:
src/SDL/MyOpenGLView.m:327:2: error: format not a string literal and no format arguments [-Werror=format-security]
  327 |  OOLog(@"display.initGL", @"Achieved color / depth buffer sizes (bits):");
      |  ^
cc1obj: some warnings being treated as errors

This PR fixes the issue on my system.

[AnotherCommander]

Begin rant: Why on Earth is this treated as an error on Fedora? It is perfectly legal Obj-C syntax and should at the worst case be flagged as a warning. The proposed fix works of course (and it is not the first tine we've had to apply something like this either) but the code is more confusing and less readable after it has been applied. And, just to be clear, I am not trying to be harsh to anyone, just trying to understand why some versions of gcc seem to be so extremely pedantic, to the point of refusing legal syntax.

Another fix that will work perfectly fine and without any security risk would be to set the -Wno-error=format-security flag somewhere in GNUmakefile.

End rant. Phew. :-)

Since we have already applied similar things in the past, this PR will most likely make it to merge. Just to be sure that there will be no more of those though, was that the only occurrence? Does the build succeed after you have corrected it?

[bcoconni]

Another fix that will work perfectly fine and without any security risk would be to set the -Wno-error=format-security flag somewhere in GNUmakefile.

Yes, but I don't feel comfortable disabling security related flags even when they seem pedantic. Furthermore, a similar issue has already been discussed in the PR #198 but the subject has been dropped at the time. However the changes have eventually found their way to the code (see commit 0b12ed3 for example). So, long story short, I have submitted this PR.

Since we have already applied similar things in the past, this PR will most likely make it to merge. Just to be sure that there will be no more of those though, was that the only occurrence? Does the build succeed after you have corrected it?

Yes, the build succeeds once the attached patch is applied and oolite runs smoothly 😄