[perl #80764] "open FH, '<:raw', $filehandle" makes filehandle unbuffered

The attached patch makes «open FH, ':raw' $filename» do what it
advertises to do: open the file, and then call «binmode FH». Previously
a shortcut was taken that simply wasn't correct, as previously explained.

I have only tested it on Linux though, testing on Windows is required.

• [perl #80764] "open FH, '<:raw', $filehandle" makes filehandle unbuffered by fawaka@gmail.com via RT
• Re: [perl #80764] "open FH, '<:raw', $filehandle" makes filehandle unbuffered by Eric Brine
• Re: [perl #80764] "open FH, '<:raw', $filehandle" makes filehandle unbuffered by Leon Timmermans
• Re: [perl #80764] "open FH, '<:raw', $filehandle" makes filehandle unbuffered by Eric Brine
• Re: [perl #80764] "open FH, '<:raw', $filehandle" makes filehandle unbuffered by Leon Timmermans
• Re: [perl #80764] "open FH, '<:raw', $filehandle" makes filehandle unbuffered by Eric Brine