base: support backslashes in the paths macports installs, closes https://trac.macports.org/ticket/47283
base: support backslashes in the paths macports installs, closes https://trac.macports.org/ticket/47283

Don't mangle backslashes in paths of files installed by MacPorts by disabling
escape sequence expansion for the haystack argument of strsed, which doesn't
seem like a good idea in the first place if we're using this from C or Tcl.

git-svn-id: 620571fa9b4bd0cbce9a0cf901e91ef896adbf27@134501 d073be05-634f-4543-b044-5fe20cf6d1d6

danchr/macports-base,neverpanic/macports-base,neverpanic/macports-base,macports/macports-base,macports/macports-base,danchr/macports-base