Can't require Ruby library when calling Mustache from CMake

[hartogjr]

For some reason, options are not parsed (including the -r option) when stdin is not a tty. This is likely due to line 99 in bin/mustache:
Mustache::CLI.parse_options(ARGV) if $stdin.tty?

This inhibits loading of Ruby libraries (or in my case, my own gem to add some processing options to the templates) when mustache is being called from CMake. This is because CMake provides mustache with a stdin that is not a tty.

Tried to fix this by simply removing the if-statement at the end, this works. So line 99 would become:
Mustache::CLI.parse_options(ARGV)