[Mono-list] mcs compile error.

[Edmund Zynda III]

I understand that in order to compile the latest version of mcs i need a
prebuilt version already installed. I use gentoo so I simply emerged
mono and it installed mono + mcs. The latest version gentoo allows is
0.13. Everything installs right. The mono runtime works and mcs works
but when i download the source for mcs v0.15 it starts to compile and
complains about how my mcs and corlib aren't synced. Here is a piece of
the error message:

Your mono runtime and corlib are out of sync.
When you update one from cvs you need to update, compile and install
the other too.
Do not report this as a bug unless you're sure you have updated
correctly:
you probably have a broken mono install.
If you see other errors or faults after this message they are probably
related
and you need to fix your mono install first.

How can that be?