Windows style line end \r\n on README, license, and similar essential plaintext files.
scripts/make_win_src_distribution.sh:
Some plain text files (which a Windows user might view in any editor) should have
Windows style line end \r\n (bug#5385). The tool is changed to do a systematic pass
over all files, find all relevant ones (especially "README*", "ChangeLog", "INSTALL*",
license text), and adapt them.
Included are two minor cleanups ("useless use of cat" avoided, variable setting
moved to more sensible place).