In this past we explicitly disabled Clang support due to some issue with the preprocessor. I tested it again with upstream Clang on Linux and Apple's Clang on macOS and there were no issues. Hence, this PR removes the check in the CMake script and adds the missing compiler configs for C. Note that two Clang configurations are needed, one named "Clang", the other "AppleClang", which is because CMake treats/identifies upstream Clang as different from Apple's Clang.
In this past we explicitly disabled Clang support due to some issue with the preprocessor. I tested it again with upstream Clang on Linux and Apple's Clang on macOS and there were no issues. Hence, this PR removes the check in the CMake script and adds the missing compiler configs for C. Note that two Clang configurations are needed, one named "Clang", the other "AppleClang", which is because CMake treats/identifies upstream Clang as different from Apple's Clang.