[build] Fix Gradle build on macOS 11.0 Big Sur

[prateekma]

The beta of macOS 11.0 Big Sur comes with AppleClang 12.0, which catches some more warnings with C++ code when building. Because -Werror is turned on, this inevitably leads to build failures. There were three main build failures that I've categorized below:

• wpiutil - tautological-overlap-compare

  • The build log for this error can be found here: https://scans.gradle.com/s/omj24fccxybfg
  • The fix was in this commit: 9cf7918

• opencv - c11-extensions

  • The build log for this type of error can be found here: https://gradle.com/s/4bndkaxghnipk
  • The fix was to compile with Wno-error=c11-extensions on macOS. I had to add this everywhere that OpenCV headers were included.

• wpilibOldCommands - range-loop-analysis

  • The error was as follows (fixed by replacing const auto& with const auto:

wpi::SmallPtrSetImpl<frc::Subsystem *>' does not return a reference [-Werror,-Wrange-loop-analysis]
    for (const auto& requirement : requirements) {
                     ^
/Users/prateekma/Documents/Dev/allwpilib/wpilibOldCommands/src/main/native/cpp/commands/Scheduler.cpp:235:10: note: use non-reference type 'frc::Subsystem *'
    for (const auto& requirement : requirements) {
         ^~~~~~~~~~~~~~~~~~~~~~~~~
1 error generated.

This was the build log after everything was fixed: https://gradle.com/s/hl3d6oryvnzzq

[ThadHouse]

That OpenCV error is actually a problem. Fixing it here won't fix user code. Can you check if Osx Catalina allows that warning disable? If so, we'll need to add that to native-utils, here won't fix it.

[prateekma]

@ThadHouse Opened a PR to nativeutils here: wpilibsuite/native-utils#51
Once that is merged and a new version is released, I can bump the nativeutils version in this PR and revert the changes related to that warning.

[prateekma]

@PeterJohnson I just used uint64_t and int64_t since the function that's calling these new templated methods is also on templated on NumberType being either uint64_t or int64_t and I couldn't find a definition for number_unsigned_t and number_integer_t anywhere.

[prateekma]

@ThadHouse Updated this PR to use latest nativeutils and everything is building fine on macOS 11

[ThadHouse]

We're going to need to merge #2592 first, as its got some other changes needed for new native utils.