#7 Complete quoting for parameters in "configure.ac"

[Markus Elfring]

I recommend to be more explicit where macro expansion will not be required.
http://autogen.sourceforge.net/acquoting.html
http://www.gnu.org/software/autoconf/manual/m4/Quoting-Arguments.html

https://github.com/dov/giv/blob/b3804807db3224346978be393053abf160c03190/configure.in