* libc/include/stdio.h (FILE): define __SCLE for "convert line
endings" for Cygwin.
(__sgetc): convert line endings if needed
(__sputc): ditto
* libc/stdio/fdopen.c (_fdopen_r): Remember if we opened in text mode
* libc/stdio/fopen.c (_fopen_r): ditto
* libc/stdio/freopen.c (freopen): ditto
* libc/stdio/fread.c (fread): perform CRLF conversions if __SCLE
* libc/stdio/fvwrite.c (__sfvwrite): ditto
