gcov-io.h (GCOV_CHECK, [...]): Remove.

	* gcov-io.h (GCOV_CHECK, GCOV_CHECK_READING,
	GCOV_CHECK_WRITING): Remove.
	(gcov_position, gcov_rewrite): Use gcc_assert.
	* gcov-io.c (gcov_open, gcov_write_words, gcov_write_length,
	gcov_read_words, gcov_sync, gcov_seek): Use gcc_assert.
	* libgcov.c (__gcov_merge_single, __gcov_merge_delta): Use
	gcc_assert.

From-SVN: r97392