Fix cutscene only showing a grey screen on macOS.

[christoph-heiss]

[Fixes #378]

Since the author of #509 apparently went MIA, I though I would quickly fix this up since I own a macOS machine.

After some debugging across two machines, I found the root cause.
Basically the issue was caused by a difference how the different C++ standard library implementations process formatted input.

Here is a minimal reproducer of the problem:

#include <iostream>
#include <sstream>
int main()
{
        float f;
        std::stringstream{"1234f"} >> f;
        std::cout << f << std::endl;
        return 0;
}

On a macOS machine, this returns 0. On a linux box, 1234 (as the previous code assumed).

I also included a small build failure fix when using a combination of gcc/clang and the different filesystem libraries, which I had laying around for a while now.

[JayFoxRox]

Skimmed over code, LGTM. Did not test it yet.

I don't fully understand our cmake_configure.cmake (for stdlib, this looks too compiler specific), but I'll assume the changes are good, too.

[madebr]

LGTM, is the CMAKE_CXX_COMPILER_ID on mac equal to Clang?
Can the test for AppleClang be removed from line 8 from cmake_configure.cmake?

[madebr]

That would be nice. Since the topic is Apple. 🍏

[christoph-heiss]

No, it is AppleClang (at least for the system compiler provided by XCode).

For clang installed by Homebrew, it is just Clang (which is an obscure edge-case).
I came across this when I test-compiled using g++ on macOS.

(Apple really has some platform-specific weirdness.)

[madebr]

Thanks for verifying!
Did not know this.

[JayFoxRox]

@madebr review sounds like it only reviewed the code, much like mine.
Aside from @christoph-heiss , did any other macOS user (and at least one gcc Linux user) run this for testing?

I'll probably hit merge once CI passed, if we have confirmed these touched platforms still run fine.

[madebr]

Just tested it on linux, gcc 8. rwgame still works, rwtests shows no difference in behavior.

[tsjost]

Tested on MacOS 10.13.4 with "Apple LLVM version 9.1.0 (clang-902.0.39.1)"; current master 7061813 indeed has broken initial cutscene, while this patch fixes it 👍