whether CRLF_SOURCE_FILES is defined.
(open_source_file): Use OPEN_MODE with open and openp.
(print_source_lines): Use FDOPEN_MODE with fdopen. If
CRLF_SOURCE_FILES is defined, ignore \r characters.
(forward_search_command): Use FDOPEN_MODE with fdopen.
(reverse_search_command): Likewise.
* config/i386/xm-cygwin32.h (CRLF_SOURCE_FILES): Define.
(LSEEK_NOT_LINEAR): Don't define.