updated for version 7.4.024
Problem:    When root edits a file the undo file is owned by root while the
	    edited file may be owned by another user, which is not allowed.
	    (cac2s)
Solution:   Accept an undo file owned by the current user.
Added tag v7-4-024 for changeset 00d61a47df66
updated for version 7.4.025
Problem:    Reading before start of a string.
Solution:   Do not call mb_ptr_back() at start of a string. (Dominique Pelle)
Added tag v7-4-025 for changeset 9085d32d7424
updated for version 7.4.026
Problem:    Clang warning for int shift overflow.
Solution:   Use unsigned and cast back to int. (Dominique Pelle)
Added tag v7-4-026 for changeset 6bbb2ae990c9
updated for version 7.4.027
Problem:    Another valgrind error when using CTRL-X CTRL-F at the start of
	    the line. (Dominique Pelle)
Solution:   Don't call mb_ptr_back() at the start of the line.  Add a test.
Added tag v7-4-027 for changeset 73cc7272de5e