allow compiling with xcode 10

[Preeternal]

Fix for the issue

[vonovak]

hello @Preeternal and thank you for your PR. Forgive me, I'm not super familiar with these kind of issues. Why did you pick this solution:

#if __IPHONE_OS_VERSION_MAX_ALLOWED < 130000
@interface UIColor (Xcode10)
+ (instancetype) labelColor;
@end
#endif

as opposed to using

#if __IPHONE_OS_VERSION_MAX_ALLOWED >= 130000
    if (@available(iOS 13, *)) {
        defaultColor = [UIColor labelColor];
    }
#endif

What does the proposed solution do? Is it just telling xcode 10 to "trust the developer" that there is a labelColor on UIColor? thank you!

[Preeternal]

Hello @vonovak As you know we got the error no known class method for selector 'labelColor' in xCode 10. In xcode 10 we have iOS SDK 12.5.
Because the method was introduced in iOS 13.0 SDK, we have to declare this method for SDK < 13 in some way.
About your question, why if statement with @available SDK check doesn't working, for me it also doesn't clear. Probably it happened after code obfuscation. I don't know.
But in this library you can find the similar issue and similar solution

[vonovak]

the available check is a runtime check, #if __IPHONE_OS_VERSION_MAX_ALLOWED >= 130000 is a compile-time check which is why there is no known class method for selector 'labelColor' in xCode 10 when the check is not there

[vonovak]

Thank you!