[m-rev.] for review: Add a note about bootstrapping to the bottom of the downloads page.

[Paul Bone]

Add a note about bootstrapping to the bottom of the

include/download.inc:
    As above.
---
 include/download.inc | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/download.inc b/include/download.inc
index a4c751a..a4d894d 100644
--- a/include/download.inc
+++ b/include/download.inc
@@ -90,3 +90,13 @@ via github at
 https://github.com/Mercury-Language</a>.
 </p>
 
+<p>
+Note that you need Mercury installed in order to build Mercury from git.
+In other words,
+you must bootstrap using one of the source distributions above,
+usually a recent release of the day is required for compatibility.
+See
+<a href="https://github.com/Mercury-Language/mercury/blob/master/README.bootstrap">
+README.bootstrap</a> for more details.
+</p>
+
-- 
1.8.1.3