Allow multi-word "install" command.
Autoconf can determine that the correct install command includes flags,
e.g., "/usr/bin/install -c". When using this as a command, we can't
enclose the value in double-quotes, as that makes some shells use the
whole expression as a filename:
# this is the value returned by autoconf and stored in CT_install
$ ins="/usr/bin/install -c"
# if we call it with quotes, the command is not found
$ "${ins}"
bash: /usr/bin/install -c: No such file or directory
# removing the quotes lets it work as expected
$ ${ins}
/usr/bin/install: missing file operand
Try `/usr/bin/install --help' for more information.
Signed-Off-By: Anthony Foiani <anthony.foiani@gmail.com>