docs build failure with doxygen 1.9.1

The following warning/errors fail the build with doxygen 1.9.1:

warning: Tag 'COLS_IN_ALPHA_INDEX' at line 135 of file 'Doxyfile' has become obsolete.
         This tag has been removed.

  clients/include/drmemtrace/drmemtrace.h:76:
  warning: argument 'mode_flags' of command @param is not found in the
  argument list of drmemtrace_open_file_func_t(const char *fname, uint
  mode_flag)

  
  clients/include/drmemtrace/drmemtrace.h:86:
  warning: The following parameter of drmemtrace_open_file_func_t(const char
  *fname, uint mode_flag) is not documented:

    parameter 'mode_flag'