[PATCH] ccache: don't use non-ASCII quotes

[David Adair]

> I would rather prefer to disable[1] the documentation.
> 
> 1. https://github.com/ccache/ccache/pull/842

Thank you.  Zero maintenance is much better.

Since master has been updated to 4.2.1 which builds fine it seems no
change there is required until it also has this change.

Is there any interest in placing this in 21.02 along with the Makefile
c
hange to use it ?  The build failure is specific to ccache 4.1 and does
NOT occur using default config ( ccache and sdk disabled ).