[ccache] Trouble sharing cache results when compiling with -isystem instead of -I

[Joel Rosdahl]

Robert Houghton wrote:
> Is looks like ccache v3.2.1 will not use the CCACHE_BASEDIR option when
> considering paths provided by -isystem. Is this intentional, an oversight,
> or a bug?

ccache does recognize -isystem, but only when used like "-isystem foo", not
in the form "-isystemfoo" (it's news to me that GCC accepts that strange
variant)... So try adding a space.

-- Joel