Use RStudio ssh & scp on windows

[hadley]

From JJ: "I've added scp.exe to the Windows MSYS SSH bundle (it's in the latest
daily build, v0.98.13). You can access the path to the directory
containing ssh.exe, scp.exe, etc. via the environment variable
RSTUDIO_MSYS_SSH"

[sckott]

Great! should this be in #81 ?

[Kvit]

Here is what I found :

• ssh wrappers in analogsea cannot findlocation of scp.exe via variable RSTUDIO_MSYS_SSH
• clp / sftp utilities themselves cannot correctly find the location of identity files / certificates or known_host files on windows (they keep trying /home/ directory)

I was able to force clp / sfp utilities to work by explicitly providing information via option flags, but I don't know how to feed those options into analogsea code #155

[sckott]

thanks for the feedback @Kvit we'll see what can be done over in #155