[PATCH] Give svnmucc ability to handle multiline properties

Hi,
We use svnmucc to update externals properties as part of our build
process. As it is svnmucc doesn't allow multi-line property values
when used with -X as each newline in the extra args file means a new
argument. This is patch which we've been using to allow this. If the
argument isn't used then the behaviour is unchanged.

[[[
Allow svnmucc to set multiline properties. This is done by adding an optional
-c (--continuation-char) argument which takes a single character argument.
Any lines in the --extra-args file ending with that character will then not
terminate the current argument.

* tools/client-side/svnmucc/svnmucc.c
  (read_extra_args) New external file argument parsing function
  (usage) Updated with new argument
  (main) Update to accept new argument and call read_extra_args
]]]

As an example we are using '-c @' on a file with:

svnmucc.exe -m "hello" -c @ -X multi-line.txt

Where multi-line.txt is

propset
svn:externals
-r52792 /svn/Repo/Pools/Shared/Stuff@
-r52792 /svn/Repo/Pools/Shared/MoreStuff
https://source01/svn/Sandbox/testA

------------------------------------------------------
http://subversion.tigris.org/ds/viewMessage.do?dsForumId=462&dsMessageId=2371714