DOS/Windows-specific code: source.c

[Eli Zaretskii <eliz at is dot elta dot co dot il>]

    * source.c:openp()

    #ifdef _WIN32
      mode |= O_BINARY;
    #endif

I think this is obsolete and should be removed: defining
CRLF_SOURCE_FILES in xm-whatever should solve the underlying problem.

For those who don't know: the problem here is that find_source_lines
creates a table which records the byte position of each line in a
source file, but many DOS/Windows libraries don't DTRT with byte
offsets unless the file is open in binary mode.  So this issue is
limited to source files, and CRLF_SOURCE_FILES should provide the
solution there for Windows systems.

(Code which wants to open binary files, like in exec.c, already uses
O_BINARY when it calls openp.  Hmm, perhaps solib.c should be fixed to
use O_BINARY when it looks for the libraries.)