Patch for allowing whitespace in file names

[heiner0]

The attached patch fixes

[1960894] libssh2_scp_* do not handle whitespace in file names

It introduces a new (private) function

libssh2_shell_quotearg()

for "quoting" a shell command argument (e.g. a file name). Example:

one two

gets converted to

'one two'

(note the single quotation marks).

The quoting style ensures that the results
work with both Bourne Shell derivates (sh, ksh, ksh93, bash, zsh) and C-Shell dialects (csh, tcsh).

The new (private) macro

libssh2_shell_quotedsize()

calculates the maximum size a quoted string can have; this is useful for allocating a memory buffer for the
results.

I've tested the code with

Linux: bash, ksh93, tcsh
Solaris: sh, bash, csh

[heiner0]

Patch for allowing whitspace in file names

[heiner0]

This entry is a duplicate of 1960894 and can be close.