message: Use va_copy instead of __va_copy to fix building libomp against musl libc
  Fixes
  Patch by Peter Levine
diff: @@ -168,7 +168,7 @@ void __kmp_str_buf_vprint(kmp_str_buf_t *buffer, char const *format,
  #if !KMP_OS_WINDOWS
  va_list _args;
  - __va_copy(_args, args); // Make copy of args.
  + va_copy(_args, args); // Make copy of args.
  #define args _args // Substitute args with its copy, _args.
  #endif // KMP_OS_WINDOWS
  rc = KMP_VSNPRINTF(buffer->str + buffer->used, free, format, args);
  