Can't compiler lib/osgl with OpenMP enabled on OSX

[clyne]

Compiling with OpenMP support on OSX requires using the vanilla clang compiler (not Apple's bundled bastardization of clang). Compilation is failing as shown below:

[ 10%] Building C object lib/osgl/CMakeFiles/osgl.dir/glad/src/egl.c.o
In file included from /Users/clyne/src/vapor/lib/osgl/GLContextProviderMacOS.mm:2:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.1.sdk/System/Library/Frameworks/AppKit.framework/Headers/NSOpenGL.h:9:
In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.1.sdk/System/Library/Frameworks/Foundation.framework/Headers/Foundation.h:12:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.1.sdk/System/Library/Frameworks/Foundation.framework/Headers/NSBundle.h:91:143: error: function does not return NSString
- (NSAttributedString *)localizedAttributedStringForKey:(NSString *)key value:(nullable NSString *)value table:(nullable NSString *)tableName NS_FORMAT_ARGUMENT(1) NS_REFINED_FOR_SWIFT API_AVAILABLE(macos(12.0), ios(15.0), watchos(8.0), tvos(15.0));

cisl-benona[611] clang --version
clang version 12.0.1
Target: x86_64-apple-darwin20.6.0
Thread model: posix
InstalledDir: /opt/local/libexec/llvm-12/bin

I believe that this issue is related to #3158

Clearly we have to fix this to release. Giving the issue a milestone and assigning to @StasJ

[sgpearse]

@clyne I'm currently in the middle of debugging this for #3158. I'm going to assign to myself and if I hit a brick wall I'll include @stas.

[clyne]

This is fixed after upgrading clang compiler to clang-13. Closing.