message: Update common.h to build with "-Werror=undef"
  __clang_major__, __clang_minor__ should be accessed with clang compiler.
  This change resolves issue.
diff: @@ -84,7 +84,8 @@ typedef struct TfLiteIntArray {
  // https://github.com/google/re2/commit/b94b7cd42e9f02673cd748c1ac1d16db4052514c
  #if (!defined(__clang__) && defined(__GNUC__) && __GNUC__ == 6 && \
  __GNUC_MINOR__ >= 1) || \
  - defined(HEXAGON) || (__clang_major__ == 7 && __clang_minor__ == 1)
  + defined(HEXAGON) || \
  + (defined(__clang__) && __clang_major__ == 7 && __clang_minor__ == 1)
  int data[0];
  #else
  int data[];
  